Display quality inspection
1, external process inspection: external bezel design, production process rigor can be seen on the whole screen of professionalism (reflected in the corners, paint, wrong seams, gaps, firm, flatness, etc.). A stable operation
The electronic screen must be two aging test, and the total time shall not be less than 24 hours. After the electronic screen is lit by uninterrupted tapping the screen, you can check the soldering, dead lights, as well as the line
of the fastening.
2, check the internal structure: ① first view of the back of the unit board whether to do 3 anti-paint (with a fingernail back and forth gently buckle circuit boards, do not do the three anti-City is very easy to show the copper coating, most manufacturers in order to catch up with the goods is not to do
), this plays a key role in the screen's life. ② view foot: foot too long or long and short, indicating that in the process of cutting the foot for the purely manual operation, will be out of the item potential electrostatic failure
effectiveness. ③ look at the solder joints: high purity tin solder joints silver white shiny, when the solder joints appear black or black spots, the screen is not recycled old board is also very quality problems, because when the solder impurities too much will be
loose solder, false solder, but also shows that there is no three anti-processing or inventory backlog for a long time. ④ check the line: display standard line (to eliminate the flower line) should be a soft-core copper wire (power supply out of the minimum
not less than ￠ 1.5 national standard), the two ends of the special terminal clamp pressure. The color should not be too much, the length is appropriate, and comb neatly tied. ⑤ Check the power transformer: led screen power are 5v, more than 200w
for standard installation. Installation must be screwed or riveted (for heat dissipation punch face out), each power supply must be grounded, the string power supply must be L into the firewire. Maximum load with 8-10 pieces of unit board. The most
After checking the manufacturer's nameplate, factory date, etc., at present, the domestic stable power supply brands are "account Wei" "Chuanglian" "Chenglian. ⑥ control system advantages and disadvantages: led control card is equivalent to the brain, high-performance
control card directly determines the use of the effect (such as flashing screen, jumping, special effects, automatic branching, automatic paging, etc.)
3, check the flatness: the surface flatness of the display screen should be within ±? Within, such as more than this value, that is, the installation process and chassis is not flat, but also pcb board or mask deformation. In order to ensure that the display image and text does not
distortion, local convex or concave will lead to the visual angle of the display does not appear dead center. Should promptly check whether the back of the pcb hit the manufacturer's logo, year, batch number, etc.. Because the flatness
of the good and bad mainly by the responsible production process.
4, brightness and viewing angle: the brightness of the indoor screen should be in 800 cd/m? above, the brightness of the outdoor screen should be in 1500 cd/m? above, in order to ensure the normal operation of the display, otherwise
will be too low because of the brightness to see the image displayed. The size of the brightness is mainly determined by the good and bad LED tube core.
5, white balance effect: white balance effect is one of the most important indicators of the display. Color science when the ratio of red, green and blue three primary colors for 1:4.6:0.16 will show a pure white, if the actual ratio
proportion has a little deviation will appear white balance deviation, generally pay attention to the white whether there is a blue bias, yellowish-green phenomenon. The white balance is mainly determined by the control system of the display, and the tube core also has an impact on the
color reproduction.
6, color reproduction: color reproduction refers to the display of color reproduction, both the display of the color to maintain a high degree of consistency with the color of the playback source, so as to ensure that the image of the sense of reality.
7, there is no mosaic, dead pixel phenomenon: mosaic refers to the display of often bright or often black small quadrangle, both the module necrosis phenomenon, the main reason for the display of the quality of the connectors used is not
Off. Dead spot is the display of often bright or often black single point, the number of dead spots mainly by the core of the good and bad to decide.
8, with or without color blocking: color blocking refers to the presence of more obvious color differences between adjacent modules, the color transition to the module as a unit, resulting in the phenomenon of color blocking is mainly caused by the control system is poor, gray scale level is not high, the scanning frequency is low.
Zhuzhou Zeming Optoelectronics Technology Electronic Engineer --------- Shi Lijian