LED Submount Cavity Angled Sidewalls Light Extraction
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Solution Overview
Problem
Conventional white LED packages face issues with uniformity and reproducibility of light output due to the large optical image size and difficulty in controlling the distribution of wavelength conversion material.
Innovation Solution
A semiconductor light emitting device is packaged in a submount with a cavity having angled sidewalls and a recess for a solid wavelength conversion member, which is pre-tested for wavelength conversion characteristics, positioned over the device to enhance light extraction and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LED packaging with large metallic mounting cup is used, then the package structure is simple and easy to manufacture, but the optical image size becomes large and light output uniformity deteriorates
Solution Approach 1:
The patent segments the wavelength conversion function by using a pre-formed converter element with controlled phosphor distribution rather than applying phosphor coating over the entire mounting cup area. This segmentation allows the conversion function to be confined to a smaller, controlled region, reducing optical image size while maintaining manufacturing simplicity through pre-fabricated converter elements.
Solution Approach 2:
The patent applies local quality by using a converter element where the wavelength conversion material is distributed in a controlled manner within a specific volume, rather than uniformly coating the entire large mounting cup area. This localized conversion region improves light output uniformity and reduces the optical image size by confining the conversion function to where it is most needed.
2Manufacturing precision
If wavelength conversion material is distributed over large area, then the package structure is simple, but the uniformity and reproducibility of light output deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming the wavelength conversion element with controlled phosphor distribution before mounting it on the LED chip. This pre-fabrication allows precise control over the wavelength conversion material distribution, ensuring uniformity and reproducibility of light output, while the element can be readily mounted using simple conventional processes.
3Illumination intensity
If flip chip mounting is used for SiC-based LEDs, then light extraction and heat dissipation are improved, but the package complexity increases
Solution Approach 1:
The patent merges the wavelength conversion element directly onto the LED chip in a flip-chip configuration, combining the light extraction function and wavelength conversion function in a single integrated structure. This approach maintains the light extraction benefits of flip-chip mounting while simplifying the overall package by eliminating separate conversion material application steps and reducing structural complexity.
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 reduces the optical image size, improves light output uniformity, and allows for pre-manufactured wavelength converters to be used, ensuring reproducible and controlled light emission at lower costs.
Implementation Method 1
A solid wavelength conversion member is positioned on the submount over the light emitting device to receive and wavelength convert light emitted from the light emitting device
Data Source
AI summary
A submount for a semiconductor light emitting device includes a semiconductor substrate having a cavity therein configured to receive the light emitting device. A first bond pad is positioned in the cavity to couple to a first node of a light emitting device received in the cavity. A second bond pad is positioned in the cavity to couple to a second node of a light emitting device positioned therein. Light emitting devices including a solid wavelength conversion member and methods for forming the same are also provided.