Light-altering Particle Arrangements for LED Light Extraction
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Solution Overview
Problem
Solid-state lighting devices, such as LEDs, face challenges in maximizing light emission efficiency due to internal reflection and interaction with package elements, leading to light loss and suboptimal illumination characteristics.
Innovation Solution
The use of light-altering particles with specific median particle sizes, strategically arranged around LED chips and lumiphoric materials, to redirect light in desired directions, improving the overall light extraction efficiency by targeting specific wavelengths in different areas of the LED package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light-altering particles are arranged around LED chips to redirect light, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The light-altering material is divided into multiple discrete particles with different median sizes (e.g., 10-20 micrometers, 20-30 micrometers, 30-40 micrometers) arranged in specific regions around the LED chip. This segmentation allows each particle size to target specific wavelength ranges, improving overall light extraction efficiency while maintaining a manageable package structure through regional differentiation rather than uniform complexity.
Solution Approach 2:
Different regions of the LED package are assigned different particle sizes and compositions based on local light distribution characteristics. For example, larger particles may be placed in regions where longer wavelengths dominate, while smaller particles are used where shorter wavelengths are more prevalent. This local optimization improves light redirection efficiency without requiring complex uniform structures throughout the entire package.
2Productivity
If multiple light-altering particles with different median sizes are used, then light redirection efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs particles with discrete median size ranges (e.g., 10-20 μm, 20-30 μm, 30-40 μm) rather than requiring precise single-size control. This parameter discretization approach maintains manufacturing feasibility by allowing broader tolerances within each size category while still achieving wavelength-specific light redirection. The median size specifications provide clear manufacturing targets without demanding excessive precision.
Solution Approach 2:
The light-altering material comprises composite structures with particles of varying sizes and potentially different materials (e.g., TiO2, SiO2, ZrO2) combined in specific ratios. This composite approach allows each particle size range to contribute to different wavelength redirection tasks, achieving superior overall efficiency while the composite nature provides manufacturing robustness through material redundancy and tolerance to individual particle variations.
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 light redirection efficiency, increasing the amount of light emitted in desired directions, thereby improving the brightness and quality of LED illumination, especially for cool white, neutral white, and warm white applications.
Implementation Method 1
a light-altering material arranged to redirect light in a desired emission direction with increased efficiency
Implementation Method 2
photons reaching the surface (interface) between an LED surface and the surrounding environment are either refracted or internally reflected
Implementation Method 3
lumiphoric materials arranged in a light-receiving path of the LED chips
Implementation Method 4
LEDs are solid-state devices that convert electrical energy to light
Data Source
AI summary
Solid-state lighting devices including light-emitting diodes (LEDs), and more particularly LED devices with light-altering particle arrangements are disclosed. An LED device may include an LED chip with a light-altering material arranged to redirect light in a desired emission direction. The light-altering material may include light-altering particles with a median particle size that is determined based on a wavelength of light provided by the LED chip. Such light-altering particles may be arranged proximate sidewalls of the LED chip to redirect lateral emissions. LED devices may further include lumiphoric materials and other light-altering particles arranged proximate the lumiphoric materials with a median particle size that is determined based on a wavelength of light provided by the lumiphoric materials. By selectively arranging different light-altering particles in different areas of an LED device based on what wavelengths of light are most concentrated, the amount of overall light redirected may be increased, thereby improving efficiency.