1. Out of control point The out of control point of indoor LED display screen shall not be greater than 3/10000, and the out of control point of outdoor LED display screen shall not be greater than 3/1000, and shall be discrete;

2. Consistency The LED screen shall have good consistency, and the brightness of the whole screen shall be balanced without obvious color patches;

3. No potential safety hazard and leakage current, and the leakage current to the ground shall not exceed 3.5mA (effective value of AC); Resistance point strength: the LED display screen can withstand the test voltage of 50Hz and 1500V (effective value of AC) Lmin without insulation breakdown; At the same time, LED display screen shall have warning signs at the fuse and switching power supply;

4. Appearance: no obvious scratch on the outer frame of LED display screen. The outdoor LED display screen pixel tube shall be installed uniformly, without looseness or shell crack;

5. The structure and LED display screen can be made of steel, aluminum, wood and other materials. The structure shall be solid and beautiful