Basic knowledge of LED display screen（7）
284 views admin 2019-11-28
9. Playback effect required by users
(1) text display: depending on the text size and resolution requirements;
(2) general video display: 320 × 240 lattice;
(3) digital standard DVD display: ≥ 640 × 480 dot matrix;
(4) complete computer video: ≥ 800 × 600 dot matrix
10. Factors to be considered in the size design of display screen
(1) need of display content;
(2) space conditions of the site;
(3) display unit template size (indoor screen) or pixel size (outdoor screen);
(4) general length width ratio of display screen;
(5) graphic screen: determined according to the displayed content;
(6) video screen: generally 4:3 or close to 4:3; the ideal ratio is 16:9.
How to distinguish the quality of LED screen
- Flatness: the surface flatness of the LED display screen shall be within ± 1mm to ensure that the display image will not be distorted, and local bulge or concave will cause dead angle of the visual angle of the display screen. The manufacturer of vehicle LED display introduces that the flatness is mainly determined by the production process.
- brightness and visual angle: the brightness of indoor full color screen shall be 800-2000cd / m2, and the brightness of outdoor full color screen shall be 5000-7500cd / m2, so as to ensure the normal operation of the display screen, otherwise, the displayed image will not be seen clearly due to the low brightness or high brightness. The brightness is mainly determined by the size of LED core crystal. The size of the visual angle directly determines the number of the screen audience, so the larger the angle, the better. And its size is mainly determined by the packaging method of the tube core.
- white balance effect: white balance effect is one of the most important indicators of the display screen. In color science, when the ratio of red, green and blue primary colors is 1:4.6:0.16, pure white will be displayed. If there is a little deviation in the actual ratio, the deviation of white balance will appear. Generally, attention should be paid to whether white has blue or yellow green phenomenon. The white balance is mainly determined by the control system of the display screen, and the tube core also affects the color reduction.
- Whether there is color block color difference: color block refers to the obvious color difference between adjacent modules. The color transition is based on modules. The color block phenomenon is mainly caused by poor control system, low gray level and low scanning frequency.
- Color reducibility: color reducibility refers to the color reducibility of the display screen. 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.
- Whether there is mosaic or dead spot: mosaic refers to the effect of uneven color of unit module on the display screen, the small four squares that are always bright or often black, i.e. module necrosis, which is mainly caused by the poor quality of connectors used in the display screen. Dead point refers to a single point that is always bright or black on the display screen. The number of dead points is mainly determined by the quality of the pipe core.