LED Package Structure with Segmented Encapsulant
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Solution Overview
Problem
Conventional LED package structures suffer from chromatic aberration and non-uniform light output due to varying light paths through the resin, leading to reduced luminance and high fabrication costs associated with wafer-level phosphor coating processes.
Innovation Solution
An LED package structure featuring a carrier, LED chip, first encapsulant with preformed openings, bonding wires, and phosphor particles distributed within the encapsulants to ensure uniform light output, with a process involving thin-layered encapsulant formation and singulation to reduce fabrication costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphor particles are distributed in a resin to convert LED light, then white light output is achieved, but chromatic aberration occurs due to varying light paths leading to non-uniform luminance and color
Solution Approach 1:
The patent segments the encapsulant into two distinct layers: a first encapsulant layer containing phosphor particles for wavelength conversion, and a second encapsulant layer without phosphor particles for uniform light extraction. This segmentation allows each layer to perform its specific function independently, preventing chromatic aberration while maintaining luminance uniformity across different viewing angles.
2Illumination intensity
If wafer level fabrication is used to form phosphor coating layer, then uniform white light output is achieved, but fabrication cost increases significantly
Solution Approach 1:
The patent separates the phosphor coating process from wafer-level fabrication by applying phosphor particles only to the first encapsulant layer after LED chip mounting. This approach eliminates the need for expensive wafer-level processing while achieving uniform light output through the controlled distribution of phosphor particles in the first encapsulant layer.
Solution Approach 2:
The patent applies phosphor particles to the first encapsulant layer before final assembly, allowing for controlled and uniform distribution without requiring complex wafer-level processing. This preliminary action simplifies the manufacturing process and reduces fabrication costs while maintaining light output uniformity.
3Reliability
If thick encapsulant is used to cover LED chip, then complete coverage and protection are achieved, but light extraction efficiency decreases due to increased light path length
Solution Approach 1:
The patent divides the encapsulant into two layers with the phosphor-containing first layer being thinner and positioned closer to the LED chip, and the second layer providing additional coverage without excessive thickness. This segmentation optimizes both protection and light extraction by minimizing the total light path length while ensuring complete chip coverage.
Solution Approach 2:
The patent concentrates phosphor particles in the first encapsulant layer adjacent to the LED chip where light generation occurs, while the second encapsulant layer is phosphor-free and provides protective coverage. This local quality distribution ensures efficient light conversion near the source while maintaining structural protection without compromising light extraction efficiency.
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 uniform light output and high illuminating efficiency while lowering fabrication costs by using a thin-layered encapsulant with phosphor particles, enhancing light extraction and reducing chromatic aberration.
Implementation Method 1
A part of lights 152 emitted from the LED chip 110 is converted via phosphor particles 130 distributed in a resin 140, so as to output white lights 154
Data Source
AI summary
A light emitting diode (LED) package structure comprising a carrier, an LED chip, a first encapsulant, at least one bonding wire, a plurality of phosphor particles and a second encapsulant is provided. The LED chip is disposed on the carrier. The LED chip has at least one electrode. The first encapsulant is disposed on the carrier and covering the LED chip. The first encapsulant is provided with at least one preformed opening exposing at least a portion of the at least one electrode. The at least one bonding wire is electrically connected between the at least one electrode and the carrier via the at least one preformed opening. The phosphor particles are distributed within the first encapsulant. The second encapsulant is disposed on the carrier and encapsulates the LED chip, the first encapsulant and the at least one bonding wire.