Side-Emitting LED Array with Outcoupling Structures
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Solution Overview
Problem
Light emitting diode (LED) packages immersed in a glass-like medium suffer from total internal reflection, leading to low optical efficiency and increased costs due to the need for thick PVB layers, which also results in a brownish color and unpredictable light distribution at high densities.
Innovation Solution
The use of side-emitting LED packages with outcoupling structures, such as screen-printed luminescent materials, and a thin air gap between the LED and the supporting layer to enhance light distribution and reduce material usage, thereby increasing optical efficiency and visual appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LEDs are fully immersed in a glass-like medium, then durability is improved, but optical efficiency deteriorates due to total internal reflection
Solution Approach 1:
The patent introduces an outcoupling structure as an intermediary element between the LED package and the glass medium. This structure facilitates the extraction of light that would otherwise be trapped by total internal reflection, thereby improving optical efficiency while maintaining the beneficial durability of the immersed LED configuration.
Solution Approach 2:
The patent modifies the optical parameters of the system by introducing materials or structures with different refractive indices at the LED-glass interface. This parameter change enables controlled light extraction through the outcoupling mechanism, resolving the contradiction between maintaining immersion for durability and extracting light for efficiency.
2Illumination intensity
If the PVB layer is made thick to reduce LED brightness, then visual comfort is improved, but cost increases and color quality deteriorates
Solution Approach 1:
The patent segments the light distribution function by introducing outcoupling structures that act as discrete light extraction points. This segmentation allows light to be distributed across multiple locations without requiring a thick PVB layer, thereby maintaining visual comfort while reducing material usage and associated costs.
3Quantity of substance
If side-emitting LED packages are used, then material usage is reduced, but light extraction efficiency deteriorates without outcoupling structures
Solution Approach 1:
The outcoupling structure serves as a mediator that enables efficient light extraction from side-emitting LED packages. This intermediary element compensates for the reduced light extraction efficiency that would otherwise result from using thinner side-emitting LED configurations, allowing material reduction without sacrificing optical performance.
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 significantly improves optical efficiency, reduces material costs, and eliminates glare by distributing light over a larger area, creating a visually appealing and flexible LED-array system with controlled light output.
Implementation Method 1
A problem that is present for LEDs fully immersed in a glass like medium is that total internal reflection (TIR) occurs at the interface between the glass surface and the surrounding air
Implementation Method 2
the outcoupling structures may be screen printed, and the use of screen-printed structures is advantageous in terms of production speed and production costs
Data Source
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AI summary
A LED-array system comprises at least one LED package 104 arranged on a substrate 106 provided with means for supplying the LED package 104 with a drive voltage. The LED package 104 is immersed in a supporting layer 112, and the system is characterized in that the at least one LED package 104 comprises a side-emitting LED package, for emission flight essentially parallel to a surface of the substrate 106 and that the system comprises at least one out coupling structure 116 reflecting/scattering the emitted light out of the supporting layer 112.