the LED display industry also ushered in the spring, now in shopping malls, railway stations, bus stations, airports, anywhere, only where there are many people, basically will be led display rental screen figure. So the problem is, now there are many products on the market, how can you prove that you are buying a good quality screen. OK, let’s compare the data I gave you.
1. Brightness
The brightness level gives people a very intuitive feeling. You can tell the brightness level at a glance. Don’t think that the higher the brightness of the rental LED screen, the better. It depends on your use environment and viewing distance. Indoor LED electronic display screen is generally about 1000nit, outdoor LED display screen is more than 6000nit, and semi outdoor LED display screen is between 2500 and 5000nit, The brightness of the display screen with small spacing is required to be lower, about 100 to 300 nit. In short, on the premise that the audience can see the image clearly in different environments, the eyes will not feel tingling when watching for a long time.
2. Color temperature
When we see that the image color is inconsistent or different from the material on the display screen, our picture will be seriously distorted, which is related to the color temperature of the white balance of the LED display screen. If the human eye directly watches the display screen, the color temperature value of the white balance is between 6500 and 8000K, which is more suitable. If it is the display screen used by the TV station, the actual color temperature of the screen needs to be adjusted to 5500 K, so the screen on the display screen is real after recording and broadcasting through the camera.
3. Perspective
For LED display, the larger the viewing angle is, the better, so the larger the viewing range is. At present, the horizontal angle of view of indoor full-color screen can be greater than 140 degrees, and the vertical angle of view is greater than 100 degrees, while the horizontal angle of view of outdoor full-color screen is greater than 100 degrees, and the vertical angle of view is greater than 90 degrees. On the basis of clearly and completely viewing the image within the viewing angle range, the phenomenon of color deviation can not appear in different viewing angles, which is mainly related to the RGB chip packaging arrangement of LED lamps. At present, there are two arrangements in the market, i.e. pin type and vertical type. The effect comparison is shown in the following figure:
How to identify the quality level of LED display screen
4. Grayscale
When the image on the LED electronic display has poor sense of hierarchy, and the pixels are lost compared with the material, it shows that the gray level of the screen is low, and the material content can not be presented completely, clearly and truly. Its professional test method is the gray bar test, which can directly see the level of gray level. At present, the gray level of 16bit can be achieved in the industry, and then it will reach 18bit
5. Refresh rate
When the human eye directly looks at the LED display screen, it feels that the screen flickers. When the camera or camera is used for shooting, there are many horizontal dark lines, which indicates that the refresh rate of the screen is low. Under the condition of not affecting the direct viewing of human eyes, the refresh rate of the display screen can not be lower than 300Hz. To meet the requirements of cameras, cameras and other camera equipment, the refresh rate of the display screen needs to reach above 2000Hz. The following figure shows the effect comparison under high and low refresh rates:
6. Contrast
When we watch the picture of LED display screen, we feel that the picture is a little white. The gray feeling is like a layer of gauze attached to the surface, and the picture is not transparent. This shows that the contrast of this screen is low, and its contrast value can not be less than 1000:1, which is mainly related to the packaging of LED lamp and the design of module mask. The contrast of black bracket LED lamp is significantly higher than that of white bracket LED lamp The following figure shows the effect comparison:
7. Uniformity
Whether the full-color LED display screen is clean and free of pitting and mosaic is mainly related to the consistency of the brightness and color of the LED lamp. We can see the uniformity of the brightness and color by testing the screen in RGB monochrome and white state. The following figure shows the test and image effect comparison:
After we understand the functions of the display screen, a rental LED display screen with excellent display effect still needs good performance to be regarded as a high-quality display screen. We can identify it through the following aspects:
(1) Pixel out of control point (within warranty period)
The pixel out of control points are divided into blind points and constant bright points. The following figure shows the industry standard level:
How to identify the quality level of LED display screen
With the birth of small spacing screen, its industry standard can not be applied to small spacing, its standard should be higher, and its out of control rate should be controlled below 1×10-5.
(2) Protection level and safety
The higher the IP value is, the higher the protection level is
The safety is mainly reflected in the following aspects: first, leakage current, which is less than or equal to 3.5ma when the value is 1.1 times of u; second, electrical strength, which is tested at 1500V for 1min without insulation breakdown.
(3) Energy consumption and energy efficiency
In order to reduce the power consumption of LED display screen, improve the effective utilization of energy, reduce the temperature of the display screen and extend its service life, the temperature decreases by 10 ℃, and the service life of the product is doubled
A. Low VF LED
B. Low VDS constant current drive IC
C. Low impedance PCB design
D. The working voltage of the module is 4.2V and 3.8V
E. Switching power supply PFC ≥ 0.95 conversion efficiency (≥ 0.85)
(4) , reliability
Even if the display effect of an LED display screen is excellent, if its reliability is not high and the unstable failure rate is high, the quality of the LED display screen is also very low. In order to improve its reliability, we mainly consider the following aspects:
A. Material selection: material analysis
B. Thermal design: heat dissipation, heat distribution
C. Redundancy: switching power supply, controller, PCB circuit
D. Material tolerance: 20% allowance
E. Reliability simulation verification test: life, certification
Through the above detailed study from the function and performance of LED display rental screen, when we choose LED display rental screen again, we will know from which aspects to identify its quality level, so as to choose the high cost performance products suitable for ourselves.
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