How to choose LED tube?
There are countless LED fluorescent lamp companies, and the product quality and performance vary greatly, so non-professionals such as foreign trade companies, energy-saving companies, engineering companies, and foreign-funded companies’ purchasing offices in China do not know how to distinguish the products produced by each company in the process of purchasing products. The quality and performance of LED fluorescent lamps are unknown when purchasing products. Buying LED fluorescent lamps can be purchased from the following aspects: profiles, power supplies, chips
1. Profile and structure
There are two types of profiles: all-plastic and half-plastic and half-aluminum pipes.
1. All-plastic tube: The early LED fluorescent lamp used all-plastic tube, because it mainly used non-isolated power supply, in order to avoid the problem of electric shock, it is more desirable to use all-plastic tube. The biggest problem of this kind of fluorescent lamp is the heat dissipation problem. The light decay is very serious. The straw hat tube has a very short lifespan, and it breaks in less than 2000 hours.
2. Semi-plastic and half aluminum tube: The LED fluorescent lamps sold on the market are basically half PC and half aluminum alloy. Plastic is used for the half that needs light transmission, and the half that does not need light transmission but needs heat dissipation. Aluminum alloy. The power supply is of course placed in the aluminum tube, so that the heat generated by the LED plus the heat generated by the power supply is quite large, because the power of this kind of lamp is usually about 20W. If the power is bigger, half of the aluminum tube will not solve its heat dissipation problem.
2. Power supply (core issue)
The power supply of LED fluorescent lamp is divided into two kinds of built-in type and external type. Built-in means that the power supply can be placed inside the tube. The biggest advantage of this built-in type is that it can be made to directly replace the existing fluorescent tube without any circuit changes. Therefore, the built-in shape is made into a long strip to fit into the semi-circular lamp tube.
1. Non-isolated constant current power supply: Non-isolated means that there is a direct connection between the load end and the input end, so there is a risk of electric shock if the load is touched. The advantage of the non-isolated constant current source is that the circuit design is simple and the manufacturing cost is not high. The disadvantage is that the high voltage of the AC power supply will be introduced to the load end, causing the risk of electric shock.
2. Isolated constant current power supply: Isolated type refers to the isolation transformer at the input end and output end. But it can isolate the input and output. The advantage of isolating the constant current source is that the circuit design is complicated. The disadvantage is that the efficiency of the power supply will be reduced, the manufacturing cost is high, and the volume is relatively large. It is OK to put the T10 tube, but the T8 tube is more tight.
3. External power supply: In order to get the highest performance, it is best to use a centralized external power supply. At present, the main places to promote LED fluorescent lamps are government agencies, offices, shopping malls, schools, underground parking garages, subways and other places. Often a room uses more than one fluorescent lamp, possibly more than 10. At this time, a centralized external power supply should be used. A high-power AC/DC switching power supply is used for unified power supply, and each fluorescent lamp uses a separate DC/DC constant current module. In this way, the highest efficiency and the largest power factor can be obtained. The advantages of centralized power supply are obvious. Moreover, it is also an isolated power supply, this structure is also very easy to implement various dimming schemes,
Third, the chip
Under normal circumstances, there are mainly first-line brands such as CREE, Osram, Hewlett-Packard (HP), Nichia, Toyoda Gosei Lumileds, etc. The second-tier brands include Epistar (Epistar) abbreviation: ES, (Lianquan, Yuankun, Lian Yong, Guolian), Guanggal Optoelectronics (Huga), New Century (Genesis Photonics), Huashang (Arima Optoelectronics) abbreviation: AOC, Tekcore, Kellett, Juxin, Guanghong, Jingfa, Vision, Zhoulei, Liansheng (HPO), Hanguang (HL), Optical Lei (ED), Tyntek (Tyntek) Abbreviation: TK , Yao Fu Zhou Technology TC, Formosa Epitaxy (Formosa Epitaxy), Guotong, Lianding, New Optoelectronics (VPEC) and so on. Currently used in fluorescent lamps are specifications such as 3528, 3020, 3014, etc. These specifications are mainly due to their different sizes and heat dissipation methods of the chips. Chips of the same brand are packaged by different manufacturers and their quality is also different.
Four, other
1. Fixed ends: At present, there are many ways of joints, including aluminum skin, PC material, and aluminum skin plus PC material. According to the fixing method, there are glue fixed on both ends of the lamp tube, and screws can be used to fix the two tubes of the lamp tube. The method of fixing with screws is adopted by the majority of consumers.
2. The light transmittance of the PC mask: the light transmittance of the transparent mask can reach 94-98%, and the light transmittance of the fog mask is 80-86%. If the luminous flux of a lamp tube without a mask is 2000lm, plus a transparent mask with a light transmittance of only 88%, its actual luminous flux is only 1760lm.
If you add a transparent mask with a light transmittance of 95% to it, then its actual luminous flux is 1900lm, which is also a transparent mask. Why is there such a big difference between the two? The answer lies in the material of the mask. The materials of PC masks on the market include ordinary PC materials and optical grade PC materials. Because of the different manufacturers, the difference in light transmittance is quite large.
4. Substrate: Mount the LED chip surface on the PCB or aluminum substrate, and then fix it on the aluminum alloy radiator. The thermal conductivity of glass fiber PCB is 20w/mk, and the thermal conductivity of aluminum alloy is 200w/mk. It is better to use an aluminum substrate.
5. Lifespan: The lifespan of the lamp mainly depends on the reasonable combination of chips, power supply, heat dissipation and other aspects. In the final analysis, except for the most basic materials.
6. Light effect, the higher the light effect, to a certain extent, this lamp is doing better! The unit is LM/W. Benwei's luminous efficiency is more than 160LM, leading the industry
7. Judging the heat dissipation: A few minutes after the LED tube is lit, the tube body should heat up to prove that it is the aluminum substrate to dissipate heat. On the contrary, it is the glass fiber board to dissipate heat.
