Surface-Textured LED Encapsulation for Light Extraction
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Solution Overview
Problem
High-power LEDs experience light loss due to internal reflections at the encapsulation-air interface, leading to reduced light output, and existing solutions like adding a lens compromise heat dissipation and increase manufacturing costs.
Innovation Solution
A surface-textured encapsulation layer is applied to high-power LEDs, featuring geometric shapes that enhance light extraction by directing emitted light beyond the critical angle, eliminating the need for additional lens material and maintaining excellent heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lens is added to the encapsulation layer to extract additional light, then light output is improved, but heat dissipation deteriorates and manufacturing cost increases
Solution Approach 1:
The encapsulation layer is textured with a plurality of light extracting features having curved surfaces (spheroidal, hemispherical, or domed shapes) that redirect light paths to exceed the critical angle for total internal reflection, thereby extracting more light without adding lens material that would impede heat dissipation
Solution Approach 2:
The light extracting features are distributed across the encapsulation layer to create localized light extraction zones, allowing different regions of the encapsulation to have different optical properties while maintaining overall thermal performance
2Illumination intensity
If a lens is added to the encapsulation layer to extract additional light, then light output is improved, but manufacturing cost increases
Solution Approach 1:
The light extracting features are integrated directly into the encapsulation layer structure, merging the light extraction function with the encapsulation function, thereby eliminating the need for separate lens components and reducing manufacturing complexity and cost
Solution Approach 2:
The encapsulation layer serves multiple functions simultaneously: it protects the LED, provides electrical isolation, and extracts light through the integrated light extracting features, eliminating the need for additional dedicated light extraction components
3Ease of manufacture
If the encapsulation surface is made smooth, then manufacturing is easier, but light extraction is reduced due to internal reflections
Solution Approach 1:
The encapsulation surface is textured with curved light extracting features that naturally redirect light paths to exceed the critical angle, providing effective light extraction without requiring complex manufacturing processes
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
The surface-textured encapsulation increases optical output, improves heat dissipation, and reduces processing and manufacturing costs by optimizing light extraction without additional lens material.
Implementation Method 1
there is light loss in the encapsulation layer in the LEDs. This is due in part to internal reflections occurring at the interface between the encapsulation and the air
Data Source
AI summary
Surface-textured encapsulations for use with light emitting diodes. In an aspect, a light emitting diode (LED) array apparatus includes a plurality of LEDs mounted to a substrate and an encapsulation covering the LEDs and having a surface texturing configured to extract light, wherein the surface texturing is includes at least one light extracting feature having a diameter larger than two or more of the LEDs.