1. Sulfidation, chlorination and bromination.
The silver-plated layer on the LED display bracket contacts with sulfur-containing elements to produce silver sulfide, and contacts with nitrogen, chlorine, and bromine gases to produce light-sensitive silver halide, all of which will cause the display to become black and fail. Sulfur chlorine/bromination/bromination/bromination may occur in every link of production, storage, aging, and use of LEDs. After the black screen is diagnosed as sulfur/chlorine/bromination, the customer should select a specific sulfur removal plan based on the process of sulfur/chlorine/bromination. The sulfur/chlorine/bromine detection items implemented by Jinjian include: sulfur/chlorine/bromine from lamps, sulfur/bromine from lamps, sulfur/bromine from power supplies, sulfur/chlorine/bromine from auxiliary materials, sulfur/bromine from packaging workshops, Exhaust sulfur/bromine in the reflow soldering workshop. Since the sulfur/chlorine/bromine-containing gas enters the display screen through the gap of the silica gel or the bracket, Jinjian has also introduced an air tightness test program to further help customers improve the requirements for display materials.
2. Oxidation.
Silver can easily react with oxygen to produce black silver oxide under heat and high humidity. It is determined that the reason for the blackening of the display is that after the silver plating is oxidized, Jinjian will advise customers to check the air tightness of the display and lighting equipment to eliminate the path of moisture penetration.
3. Carbonization.
From experience, the material defects of the six major raw materials of the LED display and the process defects of the three major packaging processes may cause the display temperature to be too high, resulting in partial or overall blackening, and carbonization of the display. The LED bulb heat dissipation design is unreasonable, the thermal conductivity of the heat dissipation material is low, the power supply design is unreasonable, and too many reflow defects can also cause the display to be carbonized. Therefore, when Jinjian initially determines that the reason for the blackening of the display is carbonization, it is recommended that the customer * analyze the route of the LED display or lamp failure, dissecting the display/lamp, and find out the source of the defect or high thermal resistance.
4. Chemical incompatibility.
The blackening of the LED display may also be caused by chemical pollution, which often occurs in a sealed lamp with little or no air flow. After confirming that the blackening of the display is a chemical compatibility problem, the customer is advised to check whether the materials used in the lamp are chemically incompatible, and find out the materials that are incompatible with the display. Frequently encountered problems. However, the blackening of the display is only a surface phenomenon, and the vulcanization, chlorination, bromination, oxidation, carbonization, and chemical incompatibility of the LED display will cause the LED display to become black. In the absence of professional testing equipment and personnel, most LED manufacturers often rely on experience and guesswork when analyzing blackening failures, and lack scientific testing data.
