LED Encapsulant Phosphor Distribution for Uniform Light Output
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Solution Overview
Problem
Current light emitting devices face challenges in achieving higher brightness and uniformity due to defects during encapsulation, which affect light output performance.
Innovation Solution
The development of light emitting devices with increased reflectivity and a more uniform encapsulant, utilizing Group III nitride based LEDs coated with phosphors and arranged in specific patterns to enhance light emission and reduce defects during encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation methods are used, then manufacturing is simpler, but defects occur during encapsulation that reduce light output performance
Solution Approach 1:
The patent applies preliminary action by pre-coating the LED chip with phosphor materials before encapsulation, and by designing the encapsulant composition in advance to prevent defects. The encapsulant is formulated with specific additives before the encapsulation process to ensure uniform curing and prevent bubbles or voids, thereby improving light output performance without complicating the manufacturing process.
Solution Approach 2:
The patent uses composite materials by formulating the encapsulant as a composite material containing multiple components including silicone base resin, phosphor particles, and curing agents. This composite structure allows the encapsulant to simultaneously provide mechanical protection, optical transparency, and defect-free curing, resolving the contradiction between reliability and ease of manufacture.
2Illumination intensity
If phosphor coating is applied to convert LED light, then white light is produced, but light output intensity is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform phosphor distribution within the encapsulant. The phosphor concentration varies at different locations and depths within the encapsulated structure, allowing optimal light conversion at each zone. This gradient distribution maximizes white light output while minimizing energy loss by ensuring phosphor particles are positioned where they most effectively convert LED wavelengths.
Solution Approach 2:
The patent transitions from traditional surface phosphor coating to three-dimensional phosphor distribution throughout the encapsulant volume. By dispersing phosphor particles throughout the entire encapsulated space rather than just on the chip surface, the system captures and converts light across multiple dimensions, increasing overall white light output efficiency and reducing energy loss.
3Reliability
If encapsulation is performed to protect LED chips, then device reliability improves, but defects such as bubbles and voids are introduced
Solution Approach 1:
The patent applies parameter changes by carefully controlling the viscosity, curing temperature, and composition ratios of the encapsulant materials. The encapsulant formula is optimized with specific molecular weight polymers and curing agents that enable smooth filling and uniform curing without trapping bubbles. These parameter optimizations ensure both device protection and manufacturing precision simultaneously.
Solution Approach 2:
The patent uses intermediary substances including silane-modified polymers and catalysts that mediate between the encapsulant components to ensure uniform mixing and curing. These intermediary materials facilitate homogeneous distribution of phosphor particles and prevent void formation during encapsulation, achieving both reliable device protection and defect-free manufacturing precision.
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 results in improved light output performance, increased brightness, and reduced defects, enabling more efficient and uniform light emission while simplifying manufacturing processes.
Implementation Method 1
The phosphor coating can convert light emitted from one or more LED chips into white light. For example, LED chips can emit light having desired wavelengths, and phosphor can in turn emit yellow fluorescence with a peak wavelength of about 550 nm.
Data Source
AI summary
Light emitting devices for light emitting diodes (LEDs) are disclosed. In one embodiment a light emitting device can include a submount and a light emission area disposed over the submount. The light emission area can include one or more light emitting diodes (LEDs), a fillet at least partially disposed about the one or more the LEDs, and filling material. The filling material can be disposed over a portion of the one or more LEDs and a portion of the fillet.