LED light source is afraid of sulfur, this is because the sulfur-containing gas through its porous structure of the silica gel or scaffold gap, with the light source silver layer vulcanization reaction. LED light source appears vulcanization reaction, the product function area will be black, the luminous flux will gradually decline, the color temperature appears drift; vulcanized silver sulfide with the temperature increase in conductivity, in the course of the phenomenon, prone to leakage phenomenon; The situation is that the silver layer is completely corroded and the copper layer is exposed. As the gold wire two solder joints attached to the silver layer surface, when the stent function area silver layer is completely vulcanized corrosion, the golden ball fall off, resulting in dead lights.
LED lamps which have more than 50 kinds of raw materials, these materials which may also contain sulfur, chlorine and bromine elements. In a closed, high temperature environment, these sulfur, chlorine and bromine elements may evaporate into the gas and corrode the LED light source. So the lighting factory has the responsibility and obligation to provide sulfur-free environment to the LED light source.
LED lamps may contain sulfur / chlorine / bromine materials:
1. Power: LED built-in power there are twenty or three kinds of raw materials, including PCB board, sulfur rubber power cord and rubber insulation packaging plastics, halogen-containing flame retardant plastic, electronic components, may contain sulfur , Chlorine and bromine elements. When the power is hot, these materials will evaporate sulfur \ chlorine \ bromine gas, sulfur \ chlorine \ bromine gas and nitrogenous water vapor when combined, will generate corrosive harmful gases, causing corrosion on the LED.
2. PCB board: the production of circuit boards on the market have a certain amount of sulfur residue, although the PCB circuit board manufacturers in the process of cleaning the plate will eliminate the residual sulfur chemical solvent residues, but the general production process more difficult Clean and clean.
3. Sulfur-containing rubber power cord and rubber insulation packaging Plastic: vulcanized rubber can be -65 ~ 250 ℃ temperature range of long-term flexibility, and has excellent electrical and chemical stability, waterproof, ozone resistance, weather resistance Aging, coupled with the use of simple, process applicability, and therefore widely used in the electronics industry, as the electronic components of the coating, potting, packaging materials.
4. halogen-containing flame retardant materials: printed circuit board, shell, plastic, aluminum substrate insulation: PBB, PBDE, TBBP-A, PCB, hexabromododecane, tribromophenol, short chain chlorinated paraffin and other halogen compounds Often used as a flame retardant, used in printed circuit boards, shell, plastic and other materials. These materials are heated to a certain temperature, will evaporate a halogen-containing gas, halogen-containing gas and nitrogen-containing water vapor, will produce corrosive harmful gases, the LED corrosion. According to many scientific studies, halogen-based flame retardants have become contaminants that proliferate everywhere in the everyday environment, releasing harmful substances during combustion and heating, threatening the health, the environment and the next generation of descendants of the human body. The use of halogen-based flame retardants is contrary to the environmental performance of LEDs. Therefore, the proposed inspection of LED materials suppliers as far as possible the choice of halogen-free flame retardant materials.
5. Solder Paste Flux: The activator component in the flux usually contains a few halogen or organic acid components. It acts to quickly eliminate the oxide film on the surface of the metal being welded, reducing the surface tension of the solder, allowing the solder to spread rapidly. surface. The halogen is usually used bromine / chlorine, can make silver into black silver bromide / silver chloride.
6. Ink: green on the PCB board, white oil on the aluminum plate, characters, lamps and radiators on the paint may be sulfur. This is because the paint in the crude oil in the sulfide, its composition is very complex, there are elements of sulfur, hydrogen sulfide, thiols, thioethers, disulfide and so on. Among them, active sulfides, such as hydrogen sulfide, mercaptans and elemental sulfur, can react chemically with silver. Paint crude oil contains oil field water, will contain sodium chloride, magnesium chloride and calcium chloride and other salts. In crude oil processing, magnesium chloride and calcium chloride are susceptible to thermal hydrolysis, resulting in a strong corrosive hydrogen chloride. Therefore, the proposed inspection of LED materials suppliers choose sulfur-free or low-sulfur crude oil as a paint material.