LEDs have many ways to achieve white light, and the way to develop earlier and industrialized is to apply fluorescent powder on the LED chip to achieve white light emission.
LEDs use fluorescent powder to achieve white light. There are three main methods, but they are not fully mature, which seriously affects the application of white LEDs in lighting. Specifically, the first method is to apply a yellow phosphor powder that can be excited by blue light on the blue LED chip, and the blue light emitted by the chip complements the yellow light emitted by the phosphor powder to form white light. This technology is monopolized by Nichia Corporation of Japan, and a principle disadvantage of this scheme is that the emission spectrum of Ce3+ ions in the phosphor does not have continuous spectral characteristics, and the color rendering property is poor, which is difficult to meet the requirements of low color temperature illumination, and simultaneously emits light. The efficiency is not high enough and needs to be improved by developing new high-efficiency phosphors.
The second implementation method is that the blue LED chip is coated with green and red phosphor powder, and the blue light emitted by the chip is combined with the green light and the red light emitted by the phosphor powder to obtain white light, and the color rendering property is good. However, the effective conversion efficiency of the fluorescent powder used in this method is low, and in particular, the efficiency of the red fluorescent powder needs to be greatly improved.
The third method is to apply three primary colors or a plurality of colors of phosphor powder on a violet or ultraviolet LED chip, and use the long-wave ultraviolet light (370 nm-380 nm) or violet light (380 nm-410 nm) emitted by the chip to excite the firefly. White light emission is achieved by light powder.
Intematix is ​​the first research institute in the mainland to conduct research on high-efficiency low-light fading phosphors for LEDs. The company has developed a variety of color LEDs using phosphor powder through joint research with Taiwanese partners.
About LED Fluorescent Powder
There are many ways to realize white LEDs. The most common and most mature one is to mix blue light and yellow light into white light by applying a layer of yellow fluorescent powder on the blue chip. Therefore, the material of the fluorescent powder is white LED. The attenuation has a great impact.
The most popular fluorescent powder in the market is YAG yttrium aluminum garnet phosphor powder, silicate phosphor powder, nitride phosphor powder, and blue LED
Compared with phosphor powder, the chip has the function of accelerating aging white LED, and the phosphor powder of different manufacturers has different effects on the light decay, which is closely related to the raw material composition of the phosphor powder. Intematix's white phosphors have greatly improved the attenuation control of white LEDs compared to their counterparts.
LED phosphor powder dispensing step
LED fluorescent powder dispensing process is a very important part of LED production process!
Ready to work:
1. Turn on and check all LED production equipment
2. Clean the small beaker used for the glue with acetone.
3. Prepare the required mass production specifications or corresponding contact sheets, and the corresponding type of glue, and confirm that they are all within the effective period of use.
Start dispensing with glue:
1. Description of the order of the glue: The sputum agent + A glue is mixed in proportion, and the result is added the fluorescent powder + B glue in proportion to the mixture. Vacuum again afterwards.
2. Calculate the required weight of each material according to the proportion of the phosphor powder and the quantity of production in the “Production Specification†or the engineering notice.
3, adjust the precision electronic said four bases so that the electronic scale is horizontal.
4. Place the clean small beaker on the precision electronic scale. After the estimation, according to the ratio of the phosphor powder in the mass production specification, weigh the required weight of the phosphor powder and the A and B glue respectively.
5. Stir the prepared fluorescent powder by hand for 20 minutes to 30 minutes until the phosphor powder is evenly distributed.
6. Vacuum the prepared fluorescent glue until the bubble is not visible. After taking it out, use it on a clean glass cover at room temperature. Stir in the same direction for 2 minutes to 3 minutes before use. Stirring speed per Turn 2 seconds to 3 seconds.
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