The surface flatness of the LED display screen shall be within ± 1mm to ensure that the display image is not distorted, and local bulges or recesses will lead to dead angle of the display screen. The flatness is mainly determined by the production process.
2、 Brightness and visual angle
The brightness of the indoor full-color screen should be above 800cd / m2, and the brightness of the outdoor full-color screen should be above 1500cd / m2, so as to ensure the normal operation of the display screen. Otherwise, the displayed image will not be seen clearly because the brightness is too low. The brightness is mainly determined by the quality of the LED die.The size of the viewing angle directly determines the audience of the display screen, so the larger the better. The size of the viewing angle is mainly determined by the packaging method of the die.
3、 White balance effect
White balance effect is one of the most important indicators of the display screen. In terms of color theory, pure white will be displayed when the ratio of red, green and blue primary colors is 1:4.6:0.16. If there is a little deviation in the actual ratio, there will be a deviation in the white balance. Generally, it is necessary to pay attention to whether the white color is blue or yellow green. The white balance is mainly determined by the control system of the display screen, and the die also has an impact on the color reduction.
4、 Reducibility of color
The color reduction refers to the color reduction of the display screen, that is, the color displayed on the display screen should be highly consistent with the color of the playback source, so as to ensure the authenticity of the image.
5、 Are there mosaics and dead spots
Mosaic refers to the small four squares that are always on or always black on the display screen, i.e. the module is necrotic. The main reason is that the quality of the plug-in program used by the display screen is poor.Dead point refers to a single point that is always on or always black on the LED display screen. The number of dead points is mainly determined by the quality of the die.
6、 Whether there are color patches
The color block refers to the obvious color difference between adjacent modules. The color transition is based on the module. The color block phenomenon is mainly caused by poor control system, low gray level and low scanning frequency.