Vacuum Suction Phosphor Coating for LED Uniformity
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Solution Overview
Problem
Existing methods for applying phosphor to LEDs result in non-uniform coating weights and low phosphor use efficiency, leading to defects like yellowing or bluing and increased material costs due to inefficient resource utilization.
Innovation Solution
A method involving the application of phosphor powder or granular material to a substrate using a differential pressure system, allowing for uniform coating weights and high recycling efficiency by forming multiple thin layers with precise control over the coating weight per unit area, utilizing a combination of suction and ejection ports and a vacuum environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If slurry is applied using ordinary dispensing or spraying, then phosphor can be applied to LED surface, but the slurry layer formed on surface and side of LED is not uniform, leading to non-uniform color temperature and defects
Solution Approach 1:
The patent replaces conventional mechanical dispensing or spraying systems with a vacuum suction-based material transfer system. The vacuum system creates a pressure differential that uniformly draws phosphor powder through a carrier gas stream, eliminating the non-uniform coating defects caused by mechanical spray methods while ensuring consistent phosphor distribution across LED surfaces.
Solution Approach 2:
The patent changes the fundamental parameter of material delivery from positive pressure (spray) to negative pressure (vacuum suction). This parameter reversal enables uniform phosphor coating by allowing the vacuum to evenly draw material through the carrier gas, creating consistent coating thickness and uniform color temperature across the entire LED surface.
2Quantity of substance
If dam or reflector is used to control slurry application, then phosphor quantity can be controlled, but the process becomes complex and requires larger quantity of binder
Solution Approach 1:
The patent eliminates the need for mechanical dams or reflectors by using a vacuum-based material transfer system. The vacuum suction directly controls phosphor quantity through pressure differential regulation, simplifying the process while enabling precise phosphor-to-binder ratio control without requiring additional structural components.
Solution Approach 2:
The vacuum system automatically regulates phosphor application quantity through pressure differential control, eliminating the need for external damping structures. The system self-regulates the phosphor flow based on vacuum level, reducing process complexity while maintaining precise material quantity control.
3Ease of manufacture
If larger quantity of binder is used to improve slurry fluidity, then slurry can be applied, but film thickness becomes larger than required, leading to light loss
Solution Approach 1:
The patent replaces slurry-based application with a powder vaporization system using carrier gas and vacuum suction. This eliminates the need for binder to achieve fluidity, as the phosphor powder is directly transported through the gas stream. The resulting film thickness is precisely controlled by vacuum level and gas flow, minimizing light loss while maintaining ease of application.
Solution Approach 2:
The patent changes the material state from liquid slurry to powder particles suspended in carrier gas. This parameter change eliminates the binder requirement for fluidity control, allowing direct control of phosphor quantity through gas flow and vacuum level parameters, thereby reducing film thickness and light loss.
4Manufacturing precision
If phosphor is applied on entire substrate, then coating can be formed, but use efficiency of phosphor is very low
Solution Approach 1:
The patent applies phosphor locally only where needed on the substrate surface rather than uniformly across the entire substrate. The vacuum suction system can be positioned to target specific LED chip areas, ensuring phosphor is deposited only on the active coating regions, thereby significantly improving phosphor use efficiency while maintaining precise coating formation.
Solution Approach 2:
The patent segments the substrate into coated and uncoated regions, applying phosphor only to the necessary areas for LED chip coating. This segmentation approach, enabled by precise vacuum positioning, reduces phosphor waste while ensuring complete coverage of the active substrate areas requiring coating.
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
Achieves high-quality, uniform phosphor deposition on LEDs with significantly improved phosphor use efficiency, reducing material costs by up to ten times and minimizing defects such as yellowing or bluing.
Implementation Method 1
providing means for creating a differential pressure between the suction port and the ejection port
Implementation Method 2
suck the powder or granular material on the substrate
Implementation Method 3
the phosphor on the substrate may be sucked and applied to an LED or LED component set in a vacuum atmosphere
Implementation Method 4
volatile components may be evaporated in the case where a slurry is used
Data Source
AI summary
[Object] To apply or deposit powder or granular material onto a required portion of an object by a required quantity precisely at low cost, to make the weight per unit area smaller than one square centimeter or square millimeter uniform, and to make the use efficiency of powder or granular material as close to 100% as possible.[Solution] Firstly layers of powder or granular material is formed on a substrate with a uniform weight per unit area, and then the powder or granular material on the substrate is sucked and ejected toward the object to form layers or films.