LED Spacer Layer for Light Extraction Efficiency
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Solution Overview
Problem
Conventional LED packages face challenges in achieving high light emission efficiency due to internal reflection and unintended propagation of light-altering materials, which reduces the extraction of light in the desired direction, especially in smaller package sizes with multiple LED chips.
Innovation Solution
Incorporating a spacer layer in the LED package to cover rough surfaces and gaps between LED chips, combined with a light-altering material that is strategically positioned to redirect light efficiently, thereby reducing interference with desired emissions and enhancing light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a light-altering material is applied to the LED package to redirect light, then light emission efficiency is improved, but the material may unintentionally propagate toward LED chips and interfere with desired light emissions
Solution Approach 1:
The spacer layer acts as an intermediary barrier between the light-altering material and the LED chips. It is applied to the submount before the light-altering material, creating a physical boundary that prevents the light-altering material from propagating onto the LED chips while still allowing the light-altering material to function in redirecting light emissions in the desired direction.
Solution Approach 2:
The spacer layer divides the LED package surface into distinct functional zones: areas where the light-altering material is allowed to reside (for light redirection) and areas where it is blocked (LED chip surfaces). This segmentation prevents harmful propagation while maintaining the beneficial light-altering function in appropriate regions.
2Productivity
If multiple LED chips are arranged in a smaller package to increase light output, then productivity is improved, but gaps and rough surfaces between chips cause internal reflection and reduce light extraction efficiency
Solution Approach 1:
The spacer layer is selectively applied to specific locations where gaps and rough surfaces exist between LED chips, providing localized smoothing and light management exactly where needed. This targeted approach addresses the light extraction efficiency problem in gap regions without interfering with the light emission function of the LED chips themselves.
Solution Approach 2:
The spacer layer converts the harmful effect of gaps and rough surfaces (which cause internal reflection and light loss) into a beneficial light-managing interface. By filling and smoothing these irregularities, the spacer layer creates an optimized optical pathway that improves light extraction efficiency while maintaining the compact multi-chip package structure.
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 spacer layer arrangement improves light emission efficiency and uniformity by preventing unintended propagation of the light-altering material, allowing for more effective redirection of light emissions in the desired direction, thus enhancing the overall light output and emission profile of the LED package.
Implementation Method 1
a lumiphoric material on the second face
Implementation Method 2
A light-altering material is arranged to redirect light in a desired emission direction
Implementation Method 3
A light-altering material is arranged to redirect light in a desired emission direction
Data Source
AI summary
Solid-state lighting devices including light-emitting diodes (LEDs), and more particularly LEDs and packaged LED devices with spacer layer arrangements are disclosed. An LED package may include one or more LED chips on a submount with a light-altering material arranged to redirect light in a desired emission direction with increased efficiency. A spacer layer is arranged in the LED package to cover rough surfaces and any gaps that may be formed between adjacent LED chips. When the light-altering material is applied to the LED package, the spacer layer provides a surface that reduces unintended propagation of the light-altering material toward areas of the LED package that would interfere with desired light emissions, for example over LED chips and between LED chips. In various arrangements, the spacer layer may cover one or more surfaces of a lumiphoric material, one or more LED chip surfaces, and portions of an underlying submount.