[Text|High-tech LED Ganqin] In LED packaging, the performance of white LED devices depends to a large extent on the performance of the phosphor. The brightness of the phosphor is mainly determined by its chemical composition, crystal structure and particle morphology. The particle morphology and particle size distribution of the phosphor not only play a key role in the performance of the LED package, but more importantly, it can further reduce the cost of the package.
The industry believes that the shape of the phosphor particles is good or not, which directly affects the initial luminous flux and light decay of the LED device. The better the morphology of the phosphor particles, the smaller the light decay of the LED device after encapsulation. For the same type of phosphor, the brightness of the crystals with good crystallization and regular particle morphology is usually high. This rule applies to all types of phosphors. .
In order to avoid such a situation, some manufacturers use a method of adding a co-solvent to reduce the particle size of the phosphor particles and improve the uniformity of the phosphor particles, so that the phosphor particles tend to grow spherically. The morphology of the phosphor particles obtained by this method is a relatively regular spheroidal shape, and the surface is not only smooth but also has good particle dispersibility.
Liu Ronghui, director of the research and development department of Rare Earth LED Luminescence, introduced the rare earth through technological innovation and successfully launched a spheroidal nitride red phosphor. Its overall shape tends to be spherical, and the rhombus is round and round, compared with the phosphor of conventional morphology. The spheroidized phosphor has high light efficiency and good stability, and has excellent properties such as easy dispersion in the encapsulant, especially in low-flow encapsulated silica gel.
“The spheroidized phosphor has good surface crystallinity and few defects, so it has good temperature characteristics, is more suitable for high power packaging and is applied to a wider temperature range, and has better application effect in the field of COB and filament lamps.†Liu Ronghui If so.
In the LED package, only paying attention to the particle shape of the phosphor is not enough. The particle size distribution of the phosphor is also one of the important factors affecting the LED package. The "dispersion" is usually used to describe the relative width or unevenness of the particle size distribution. It can be expressed as the ratio of the particle size distribution width to the center particle diameter. Therefore, the dispersion of phosphors is also receiving serious attention in LED packaging.
Zhao Kun said, “In general, the greater the dispersion, the more uneven the particle distribution in the phosphor. Conversely, the smaller the dispersion, the more uniform the particle distribution in the phosphorâ€.
According to the experiment, Xinli Light Source showed that there were significant differences in the BIN performance of LED devices encapsulated by different dispersion phosphors. LED products packaged with less discrete phosphors are more convergent, indicating that the cost of LED products packaged with this phosphor will be lower.
Liu Ronghui pointed out that “the current commercial red powder dispersion on the market is about 1.2~1.6, and the nitride HR-01 dispersion (D90-D10/D50) developed by Rare Earth Research is less than 0.9, which realizes the uniformity distribution of particles. Improve the Bin concentration and package yield of LED package products."
Feng Rongbiao, project manager of Keheng's LED business unit, said that the LED components of the less-dispersed phosphor package have a slightly higher luminous flux and less fluctuation in luminous flux, color coordinates and color rendering index, indicating that the particle size distribution of the phosphor is more concentrated. The better the optical parameter consistency of the encapsulated LED device.
He further stated that the phosphor particle size is different, and the amount of phosphor powder required to make the lamp of the same color is different. The finer the particle size, the less phosphor is used. "The smaller the particle size of the phosphor, the lower the degree of sedimentation in the fluorescent gel, so that the color change of the light source after baking is small, which is beneficial to the color consistency control. Secondly, the smaller the particle size distribution coefficient of the phosphor, the smaller the particle size distribution coefficient The narrower the distribution, the better the sedimentation consistency of the phosphor, and the degree of color change is close to".
Generally speaking, the particle size of the phosphor has a great influence on the color yield of the light source of the packaging factory. The more dispersed the color of the produced light source, the higher the defect rate and the more difficult the shipping. In the industry, the particle size distribution of the phosphor plays a decisive role in the whiteness concentration of the LED package. More importantly, it has a good promotion effect on the improvement of the yield of the packaging factory and the cost reduction.
However, Feng Rongbiao said that due to the difference in the packaging process of LED package manufacturers, the viscosity coefficient of the package resin used is not the same, so there is a different demand for the particle size of the phosphor. In the future, only through the close cooperation between phosphor manufacturers and LED packaging manufacturers, phosphor manufacturers will provide the most suitable phosphor matching solutions for different packaging manufacturers, thus helping packaging companies to reduce packaging costs and improve product performance and yield.
The industry believes that the shape of the phosphor particles is good or not, which directly affects the initial luminous flux and light decay of the LED device. The better the morphology of the phosphor particles, the smaller the light decay of the LED device after encapsulation. For the same type of phosphor, the brightness of the crystals with good crystallization and regular particle morphology is usually high. This rule applies to all types of phosphors. .
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In order to avoid such a situation, some manufacturers use a method of adding a co-solvent to reduce the particle size of the phosphor particles and improve the uniformity of the phosphor particles, so that the phosphor particles tend to grow spherically. The morphology of the phosphor particles obtained by this method is a relatively regular spheroidal shape, and the surface is not only smooth but also has good particle dispersibility.
Liu Ronghui, director of the research and development department of Rare Earth LED Luminescence, introduced the rare earth through technological innovation and successfully launched a spheroidal nitride red phosphor. Its overall shape tends to be spherical, and the rhombus is round and round, compared with the phosphor of conventional morphology. The spheroidized phosphor has high light efficiency and good stability, and has excellent properties such as easy dispersion in the encapsulant, especially in low-flow encapsulated silica gel.
“The spheroidized phosphor has good surface crystallinity and few defects, so it has good temperature characteristics, is more suitable for high power packaging and is applied to a wider temperature range, and has better application effect in the field of COB and filament lamps.†Liu Ronghui If so.
In the LED package, only paying attention to the particle shape of the phosphor is not enough. The particle size distribution of the phosphor is also one of the important factors affecting the LED package. The "dispersion" is usually used to describe the relative width or unevenness of the particle size distribution. It can be expressed as the ratio of the particle size distribution width to the center particle diameter. Therefore, the dispersion of phosphors is also receiving serious attention in LED packaging.
BIN concentrated fluorescent icon
Zhao Kun said, “In general, the greater the dispersion, the more uneven the particle distribution in the phosphor. Conversely, the smaller the dispersion, the more uniform the particle distribution in the phosphorâ€.
According to the experiment, Xinli Light Source showed that there were significant differences in the BIN performance of LED devices encapsulated by different dispersion phosphors. LED products packaged with less discrete phosphors are more convergent, indicating that the cost of LED products packaged with this phosphor will be lower.
Liu Ronghui pointed out that “the current commercial red powder dispersion on the market is about 1.2~1.6, and the nitride HR-01 dispersion (D90-D10/D50) developed by Rare Earth Research is less than 0.9, which realizes the uniformity distribution of particles. Improve the Bin concentration and package yield of LED package products."
Feng Rongbiao, project manager of Keheng's LED business unit, said that the LED components of the less-dispersed phosphor package have a slightly higher luminous flux and less fluctuation in luminous flux, color coordinates and color rendering index, indicating that the particle size distribution of the phosphor is more concentrated. The better the optical parameter consistency of the encapsulated LED device.
He further stated that the phosphor particle size is different, and the amount of phosphor powder required to make the lamp of the same color is different. The finer the particle size, the less phosphor is used. "The smaller the particle size of the phosphor, the lower the degree of sedimentation in the fluorescent gel, so that the color change of the light source after baking is small, which is beneficial to the color consistency control. Secondly, the smaller the particle size distribution coefficient of the phosphor, the smaller the particle size distribution coefficient The narrower the distribution, the better the sedimentation consistency of the phosphor, and the degree of color change is close to".
Fall BIN scatter plot
Generally speaking, the particle size of the phosphor has a great influence on the color yield of the light source of the packaging factory. The more dispersed the color of the produced light source, the higher the defect rate and the more difficult the shipping. In the industry, the particle size distribution of the phosphor plays a decisive role in the whiteness concentration of the LED package. More importantly, it has a good promotion effect on the improvement of the yield of the packaging factory and the cost reduction.
However, Feng Rongbiao said that due to the difference in the packaging process of LED package manufacturers, the viscosity coefficient of the package resin used is not the same, so there is a different demand for the particle size of the phosphor. In the future, only through the close cooperation between phosphor manufacturers and LED packaging manufacturers, phosphor manufacturers will provide the most suitable phosphor matching solutions for different packaging manufacturers, thus helping packaging companies to reduce packaging costs and improve product performance and yield.
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