Dispensed Reflectors for LED Packages
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Solution Overview
Problem
Conventional LED packages face challenges in manufacturing precision and cost due to the use of separate metal reflectors, which are difficult to manufacture repeatably and require complex alignment and adhesive attachment, leading to optical losses and heat retention issues.
Innovation Solution
A packaged LED design featuring a substrate with meniscus control features and encapsulant materials, including a reflective silver epoxy or silicone with silver chrome flakes, TiO2, and SiO2 particles, forming a semi-toroidal reflector around the LED chip to reflect light and manage heat, with optional wavelength conversion materials and a lens for improved light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a separate metal reflector is used in LED packages, then light reflection is improved, but manufacturing precision and cost deteriorate due to difficulty in manufacturing repeatably and complex alignment requirements
Solution Approach 1:
The patent combines the reflector function with the encapsulant material by embedding reflective particles (silver chrome flakes, TiO2, SiO2) directly into the encapsulant. This eliminates the separate metal reflector component and integrates light reflection capability into the existing encapsulant structure, thereby improving manufacturing repeatability while maintaining light reflection performance.
Solution Approach 2:
The patent uses composite encapsulant materials that combine transparent encapsulant base material with dispersed reflective particles. This composite structure provides both the protective/encapsulating function of the encapsulant and the light reflection function of metallic particles, replacing the need for separate metal reflectors and simplifying manufacturing.
2Illumination intensity
If a separate metal reflector is used in LED packages, then light reflection is improved, but device complexity increases due to additional alignment and adhesive attachment steps
Solution Approach 1:
The patent merges the reflector function into the encapsulant material itself, eliminating the need for separate attachment steps. The reflective particles are mixed into the encapsulant before curing, so the reflector becomes an integral part of the encapsulant structure rather than a separate component requiring alignment and adhesive bonding.
Solution Approach 2:
The patent extracts the reflector function from the mechanical component domain and transfers it to the material domain. Instead of using a separate metal piece that requires mechanical attachment, the reflection capability is extracted and embedded within the encapsulant material matrix, simplifying the overall device structure and manufacturing process.
3Illumination intensity
If a reflective cup is used to direct light upward, then light direction is improved, but optical losses increase due to light absorption by the reflector cup
Solution Approach 1:
The patent uses a composite encapsulant material containing reflective particles that provide light direction through reflection while maintaining high optical efficiency. The distributed reflective particles throughout the encapsulant volume can redirect light without the significant absorption losses associated with solid metal reflector surfaces, as the particles are integrated within the transparent matrix.
4Reliability
If a conventional LED package structure is used, then environmental protection is provided, but heat retention increases due to difficulty in heat extraction through leads
Solution Approach 1:
The patent employs composite encapsulant materials that can be formulated with thermally conductive additives or materials. This allows the encapsulant to maintain its protective environmental sealing function while simultaneously improving heat extraction pathways from the LED chip through the encapsulant to the package exterior, reducing heat retention issues.
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 design enhances light reflection and heat management, reduces manufacturing complexity, and improves uniformity and flexibility in light output and beam angle, while avoiding the need for separate metal reflector parts, thus addressing precision and cost issues in LED packaging.
Implementation Method 1
a first encapsulant material including a reflective material on the substrate, the first encapsulant material spaced apart from the LED chip and configured to reflect at least a portion of light emitted by the LED chip
Implementation Method 2
The reflective cup may be filled with an encapsulant material 16 containing a wavelength conversion material such as a phosphor. Light emitted by the LED at a first wavelength may be absorbed by the phosphor, which may responsively emit light at a second wavelength.
Data Source
AI summary
A packaged LED includes a substrate, an LED chip on the upper surface of the substrate, a first encapsulant material, including a reflective material, on the substrate and spaced apart from the LED chip, and a second encapsulant material on the LED chip. A method of forming a packaged LED includes forming a first meniscus control feature on a substrate and defining a first region of the substrate, forming a second meniscus control feature surrounding the first region and defining a second region of the substrate between the first meniscus control feature and the second meniscus control feature, mounting an LED chip within the first region, dispensing a first encapsulant material including a reflective material within the second region, curing the first encapsulant material, dispensing a second encapsulant material on the substrate within the first region, and curing the second encapsulant material.