LED Package Encapsulant Curved Surfaces Light Extraction
Solution Overview
Problem
Conventional LED packages face inefficiencies in light emission due to heat retention and optical losses, particularly in high-power operations, and often require toxic materials, while also producing undesirable emission profiles and environmental concerns.
Innovation Solution
The development of LED packages with encapsulants featuring planar and curved surfaces that refract and reflect light efficiently, combined with improved phosphor layer compositions and arrangements, and the use of specific silicones, allows for enhanced light emission characteristics, including higher luminous intensity and a broader emission profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED packages use hemispheric encapsulants, then light extraction efficiency is improved, but heat retention increases and optical losses occur
Solution Approach 1:
The patent employs a hemispheric encapsulant geometry that leverages curved surfaces to optimize light extraction through controlled refraction and reflection. The spherical curvature enables omnidirectional light emission while maintaining efficient optical coupling, resolving the contradiction between light extraction efficiency and heat retention by directing light pathways away from the heat-generating LED chip.
Solution Approach 2:
The patent modifies optical parameters by incorporating phosphor materials with specific refractive indices and absorption characteristics. By changing the optical parameters of the encapsulant material and phosphor composition, the system achieves improved light extraction efficiency while managing heat distribution through selective wavelength conversion and reduced optical losses.
2Ease of operation
If reflective cups are used to direct light upward, then light directionality is improved, but optical losses increase due to less than 100% reflectivity
Solution Approach 1:
The patent introduces a phosphor-embedded encapsulant as an intermediary between the LED chip and the external environment. This intermediary converts direct LED light into omnidirectional phosphor emission, eliminating the need for reflective cups and their associated optical losses while maintaining effective light directionality through the encapsulant's geometric design.
Solution Approach 2:
The patent replaces the mechanical reflective cup system with an optical conversion system using phosphor materials. Instead of relying on mechanical reflection with inherent losses, the system uses photoluminescence conversion to achieve superior optical efficiency while maintaining light directionality control through the encapsulant structure.
3Reliability
If LED chips are mounted on submounts with wire bonds, then electrical connection is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines the electrical connection function and mechanical mounting function into an integrated substrate structure. By merging the submount, wire bonds, and encapsulant into a unified assembly, the system achieves reliable electrical connections while reducing overall device complexity and streamlining the manufacturing process.
Solution Approach 2:
The patent designs the substrate and encapsulant to serve multiple functions simultaneously: providing mechanical support, establishing electrical connections, managing heat dissipation, and controlling light emission. This multi-functionality reduces the number of separate components needed, thereby decreasing device complexity while maintaining reliability.
4Adaptability or versatility
If phosphor layers are applied to convert wavelengths, then color selection is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses composite phosphor materials with inherently stable emission characteristics that are less sensitive to variations in layer thickness and composition. By selecting phosphor materials with broad emission spectra and high quantum efficiency, the system achieves versatile color selection while tolerating broader manufacturing tolerances, thereby reducing precision requirements.
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
These LED packages achieve improved light emission efficiency, reduced heat retention, and a more compact, cost-effective design with tailored emission characteristics, surpassing conventional packages in luminous intensity and emission profile, while minimizing environmental impact.
Implementation Method 1
encapsulants featuring planar and curved surfaces that refract and reflect light efficiently
Implementation Method 2
encapsulants featuring planar and curved surfaces that refract and reflect light efficiently
Implementation Method 3
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 4
Light emitting diodes generally comprise one or more active layers of semiconductor material sandwiched between oppositely doped layers. When a bias is applied across the doped layers, holes and electrons are injected into the active layer where they recombine to generate light
Data Source
AI summary
LED packages are disclosed that are compact and efficiently emit light, and can comprise encapsulants with planar surfaces that refract and/or reflect light within the package encapsulant. The LED package are also directed to features or arrangements that allow for improved or tailored emission characteristic for LED packages according to the present invention. Some of these features or arrangements include, but are not limited to, higher ratio of light source size to submount size, the used of particular materials (e.g. different silicones) for the LED package layers, improved arrangement of a reflective layer, improved composition and arrangement of the phosphor layer, tailoring the shape of the encapsulant, and/or improving the bonds between the layers. There are only some of the improvements disclosed herein, with some of these resulting in LED packages the emit light with a higher luminous intensity over conventional LED packages.