The lighting source used in human history, the first generation is the oil lamp (candle), the second generation is the incandescent lamp invented by Edison, the third generation is the fluorescent lamp, and now people are looking forward to the fourth generation light source - white LED . Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
As a new generation of semiconductor illumination source, LED (Light Emitting Diode) is widely used in signal indication, intelligent display, local illumination and special illumination because of its high efficiency, low consumption, energy saving, fast response and long life. LED is an all-solid-state illuminant, impact-resistant and non-breakable, waste-recyclable, non-polluting, reducing the generation of harmful gases such as sulfur dioxide and nitride, and the generation of greenhouse gases such as carbon dioxide. It can be called a “green†illumination source.
status quo
Development Status LED industry in Japan and the United States, most powerful technology, they have a strong R & D capabilities and innovation in new products and new LED technology, while Germany and South Korea have the advantage in LED innovation of new products and technological aspects, they It also has advanced technology in related fields such as LED manufacturing process. The Taiwan region of China has developed rapidly in the past 10 years, occupying the world's number one position in LED chip production and LED packaging.
Trends and needs
At present, the LED optoelectronic industry is still an emerging industry, involving chip manufacturing technology, packaging technology, heat dissipation technology, secondary light distribution technology, intelligent control technology and other technical fields. All countries in the world have accelerated the pace of replacing traditional light sources with LED light sources with the support of the government . The United States, Japan, the European Union, South Korea, China and Taiwan have all formulated relevant development plans.
China's LED industry started in the 1960s, 1980s formation of industry. Most of the core patent technologies are in the hands of a few large companies such as Nichia ( Nichia ), Cree , Toyoda Gosei , Lumileds and Osram . Although there are many domestic patent applications for LEDs every year , the lack of core technologies is mainly concentrated in LED packages and LEDs. In terms of the application of lamps, the Chinese mainland still owes a leading enterprise, and there are still gaps with foreign companies and Taiwan-funded enterprises.
A common white LED manufacturing method is a color conversion type, that is, a yellow phosphor is coated on the surface of a blue LED chip. At present, the main method used in China is the traditional potting process. The phosphor is mixed with the high-transmittance silicone resin and mixed under vacuum. After vacuum defoaming, a proper amount of mixed colloid is dropped into the reflector cup by a dispenser to form a phosphor by heat curing. Layers, in which how to obtain a uniform, stable fluorescent glue is a crucial one-step process. At present, domestic white LED manufacturers mainly use a public-rotation mixer to stir and mix the fluorescent glue. However, due to the physical properties of the fluorescent rubber raw material and the performance of the public-rotation mixer, the fluorescent rubber cannot be fully obtained after being mixed and mixed. The fine dispersion, ultimately, the yield of the finished product is not very high, the waste of raw materials, and the enterprise needs to spend more to achieve the target mass production. Therefore, how to obtain high-performance fluorescent glue and prepare high-quality white LED products is a problem that must be considered in the long-term development of the company.
Second, EXAKT white LED fluorescent glue dispersion solution
EXAKT three-roller advantages:
1 ) narrow particle size distributionFor each three-roller machine, the reduction of the particle size and the dispersion of the agglomerate block are all performed by the rolling pressure between the rolls and the high shear force caused by the different roller speeds, as shown in Fig. 1 .
Since all of the material is filled into the roll spacing, the particle size is precisely controlled and narrowly distributed. By adjusting the roller spacing, the particle size can be easily machined to the micron level, while other processes are relatively difficult.
Fig. 1 |
Sand mills and dispersers are relatively close to the equipment, but can only provide a higher particle size distribution - that is, the ultra-fine particles and coarse particles have a high percentage, which is Because some of the particles may be repeatedly dispersed due to the dispersing force, and some are not dispersed at all.
Fig. 2 |
2 ) Ideal for a variety of products
The three-roller can be used in a wide range of products with different viscosities, from low-viscosity materials of 200CP to viscous slurries of more than 1,000,000CP . The three-roller is capable of processing medium to high viscosity materials in very small amounts of liquid solvent. Since the liquid often does not need to be ground or dispersed, some additions can be postponed as needed.
3 ) Excellent temperature control
The three-roller provides excellent temperature control of the product as the material is in the form of a film on the roll. Therefore, the material to be processed can be heated or cooled to a desired temperature.
4 ) Environmental protection and pollution prevention
By choosing the right roller and scraper material, the user can avoid contamination with hard metal abrasives. Materials include hard chrome stainless steel, alumina, zirconia and silicon carbide.
5 ) Batch size
The three-roller machine can perfectly process large or small batches of products.
6 ) Intuitive process control
Unlike sand mills and dispersers, there are not many variables that affect material quality, which speeds up the processing and improves quality repeatability.
7 ) low cost, low loss, easy to clean
Convenient accessories, low cost operation, low cost and high quality are the decisive factors for significant cost savings.
2 , EXAKT white LED fluorescent glue dispersion solution introduction
According to the raw materials - quality, can be roughly divided
1) Â Raw material silica gel is of good quality
2) Â Raw material silica gel quality
or
Among them, when the viscosity of the fluorescent glue is tested, it can be used by Bole ( Broo)
The specific white LED fluorescent glue dispersion solution will also be adjusted according to the LED development and preparation scheme. Table 1 shows the model and main parameters of the EXAKT three-roller.
3 , program advantages
1 ) More uniform and sufficient dispersion of fluorescent glue;
2 ) The yield of white LED products is improved;
3 ) The utilization rate of raw materials of the products is improved;
4 ) The company's efficiency has been significantly improved.
Table 1 |
Third, the success story
Case: Guangzhou Hongli Photoelectric Co., Ltd.
Hongli Optoelectronics - the leader of China's white LED device. National high-tech enterprise, executive director of National Semiconductor Lighting Engineering R&D and Industry Alliance, member of China Semiconductor Lighting Technology Standard Working Group. Hongli Opto-electronic registered capital of 245.47 million yuan, with more than 100,000 square meters of garden-style industrial park, more than 40,000 square meters of high standard clean production workshop, using the most advanced LED automated production equipment, mainly produces high-end COB, HIGH POWER LEDs, High-quality devices such as SMD LEDs, such as general lighting, backlight, automotive signal / lighting, special lighting, display and other fields.
Hongli Optoelectronics LED devices are at the leading level in terms of display, light efficiency and stability. They are the first LED packaging companies in the country to pass the third-party IES LM-80 test approved by the US Environmental Protection Agency ( EPA ) .
Hongli has improved the traditional fluorescent rubber preparation process and multi-channel EXAKT three-roller dispersion process. The results show that the yield of the product has been significantly improved, and the annual purchase cost of silica gel A can save more than 300,000 yuan. Get better production benefits.
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