What is the reason why the LED strip light source turns black sometimes?

Update:22 Jul 2022
Summary:1. Oxidation: Silver will easily react with oxygen in a high...

1. Oxidation:

Silver will easily react with oxygen in a high temperature and high humidity environment to form black silver oxide.

2. Sulfurization, chlorination, bromination:

The silver-plated layer on the LED bracket will generate silver sulfide if it touches sulfur-containing gas, and if it touches acid nitrogen-containing chlorine and bromine gas, it will generate light-sensitive silver halide, which will cause the light source to become black and fail. Light source sulfur/chlorine/bromination may occur in every link of production, storage, aging, and use of LED strip light sources and lamps. After the blackening of the light source is diagnosed as sulfur/chlorine/bromination, the customer should select a detailed sulfur removal plan according to the occurrence of sulfur/chlorine/bromination.

3. Chemical incompatibility:

Blackening of LED light sources can also be caused by chemical contamination, which is often seen in sealed lamps with little or no air movement. When it is confirmed that the blackening of the light source is caused by a chemical compatibility problem, the customer will be advised to conduct a chemical incompatibility investigation on the materials used in the lamps to find out the materials that are incompatible with the light source. frequently encountered problems.

However, the blackening of the light source is only an appearance. The reasons such as vulcanization, chlorination, bromination, oxidation, carbonization and chemical incompatibility will cause the blackening of the LED light source. Due to the lack of professional testing equipment and personnel, most LED companies usually rely on experience and conjecture to analyze blackening failures, lacking scientific testing data.

4. Carbonization:

Based on experience, the data shortcomings of the six raw materials (chips, brackets, die-bonding glue, bonding wires, phosphors, and encapsulation glue) of the LED light bar light source and the disadvantages of the three major packaging processes (die-bonding, wire bonding, and glue filling) Process shortcomings may cause the light source to generate extremely high temperatures, resulting in partial or complete blackening of the light source and carbonization of the light source. Unreasonable heat dissipation planning of LED lamps, low thermal conductivity of heat dissipation materials, unreasonable power supply planning, and too many defects in reflow soldering will also cause carbonization of the light source.

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