Compact LED Package with Reflective Layer
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Solution Overview
Problem
Conventional LED packages face inefficiencies in light extraction due to optical losses from less than 100% reflectivity of reflective surfaces and heat retention issues, with hemispheric encapsulants resulting in large devices and non-ideal emission profiles.
Innovation Solution
The development of compact LED packages with planar and/or curved encapsulants and a reflective layer to enhance light extraction, utilizing a blanket conversion material layer that scatters and converts light omnidirectionally, reducing absorption and increasing emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective cup or metal reflector is used to direct light upward, then light directionality is improved, but optical losses occur due to less than 100% reflectivity and heat retention becomes an issue
Solution Approach 1:
The patent extracts the reflective function from a separate reflective cup or metal reflector component and integrates it directly into the encapsulant material itself. The encapsulant is formulated with reflective particles or structures that provide the necessary light redirection without requiring a distinct reflective component, thereby eliminating the associated optical losses and heat retention problems.
Solution Approach 2:
The patent employs composite encapsulant materials that combine transparent matrix materials with reflective particles or phases. This composite structure allows the encapsulant to simultaneously provide optical transparency for light transmission and reflective properties for light directionality, resolving the contradiction between light control and energy loss.
2Illumination intensity
If hemispheric encapsulants are used, then light extraction is achieved, but the device size increases and emission profile becomes non-ideal
Solution Approach 1:
The patent utilizes hemispheric or curved encapsulant geometries to optimize light extraction through controlled refraction and reflection at the encapsulant-air interface. The curved surface design maximizes light extraction efficiency by directing light rays at optimal angles, while the compact hemispheric form factor minimizes the overall device volume compared to flat or rectangular encapsulant designs.
3Illumination intensity
If conventional LED packages are used, then basic light emission is achieved, but emission efficiency is reduced due to absorption by reflective surfaces
Solution Approach 1:
The patent introduces an intermediary reflective encapsulant material that mediates between the LED chip and the external environment. This intermediary layer is specifically designed to reflect light back toward the emission direction while minimizing absorption losses, thereby improving overall emission efficiency compared to conventional reflective cups or metal reflectors that directly contact the LED assembly.
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 solution achieves efficient light emission with a broader emission profile and reduced heat retention, allowing for smaller, more cost-effective LED packages with improved color uniformity and emission efficiency compared to conventional designs.
Implementation Method 1
A reflective layer is included on the same surface of the submount from the edges of the light sources toward the edge of the submount
Implementation Method 2
encapsulants with planar surfaces that refract and/or reflect light within the package encapsulant
Implementation Method 3
encapsulants with planar surfaces that refract and/or reflect light within the package encapsulant
Implementation Method 4
The LED chip can be coated by conversion material comprising one or more phosphors, with the phosphors absorbing at least some of the LED light
Implementation Method 5
Some of the light reflected within the encapsulant, due, for example, to total internal reflection from planar or otherwise shaped encapsulant surface
Data Source
AI summary
LED packages are disclosed that are compact and efficiently emit light, and can comprise encapsulants with curved and planar surfaces. The packages can comprise a submount with a one or a plurality of LEDs, and in those with a plurality of LEDs each of the LEDs can emit the same or different wavelengths of light than the others. A blanket conversion material layer can be included on at least some of the LEDs and the submount. The encapsulant can be on the submount, over at least some of the LEDs, with each of the planar surfaces being vertical and aligned with one of the edges of the submount. The packages can also comprise reflective layers to minimize losses due to light absorption, which in turn can increase the overall package emission efficiency.