9 tips to easily choose the LED screen
posted:jslcdz Browse through:13time

In order to quickly judge the quality of LED display, from the perspective of all parties, the following nine important items of LED display are integrated. The first eight projects are for general LED displays, and the ninth project is for small-pitch LED displays.

Maximum brightness

Refers to the brightness of each primary color of the LED display at the highest gray level and highest brightness under a certain ambient illumination. In short, use the software to set the brightness of the light gun in the normal direction when the display is 255 white.


For the outdoor LED display, depending on the environment used, there will be different requirements for the maximum brightness. In the case of strong ambient light, the brightness of the LED display is required to be higher, so that the masses can see the content displayed on the screen. Under normal circumstances, the display screen is located south to the north, and the maximum brightness requirement is lower. As long as it reaches 4000CD/m2, the requirement can be met, while the north-facing display screen requires the brightness of the whole screen to reach 7000CD/m2, facing east and west. The south-facing request is the same, because there will be a part of the time when the sun will shine directly on the LED display. Theoretically, a brightness requirement of more than 5500 CD/m2 is sufficient.

Color temperature

When we see that the image color is inconsistent or different from the material on the display, our picture is seriously distorted, which is related to the color temperature of the white balance of the LED display. If the human eye directly views the display, its white balance. The color temperature value is suitable between 6500 and 8000K, and if it is the display screen used by the TV station, the actual color temperature of the screen should be adjusted to about 5500K, so that the picture on the display screen is real after being recorded by the camera.

Refresh rate

The refresh rate refers to the number of times the LED display shows the information being displayed completely every second. The refresh rate is too low, and the human eye will see the LED display vibrating. Usually we will see the scan line appear when shooting with the camera. Usually, the human eye requires a refresh rate of 300 Hz or more, that is, if the refresh rate exceeds 300 Hz, the LED display screen will not be shaken when viewed with the naked eye, and if the camera is used for shooting, it is generally required according to different settings of different cameras. More than 600Hz can capture the scan line.

wavelength

The wavelength determines whether the color is pure and the color is consistent. The method of resolution is very simple; if there is no professional equipment, how to distinguish it with eyes?


First: The whole screen is white, and the screen should be pure white without any other noise. If you think there is a bit of reddish or bluish, it proves that there are problems with the display material and process quality control. It will become more and more serious after using it for a long time.


Second: the red, green, and blue colors are printed. The color of the center wavelength is the positive blue color that we usually say. If it is darker or lighter, it proves to be a partial wavelength. If a certain color is inconsistent, it proves that the wave difference is too large, the high-quality display screen is in the range of the center wavelength, the blue-green wave difference is controlled at 3 nm, and the red wave difference is less than 5 nm.

Luminous tube perspective

The illuminating angle of view of the illuminating tube refers to the angle between the two viewing directions of the same plane and the normal direction when the brightness of the viewing direction drops to one-half of the brightness of the normal direction of the LED display screen. Divided into horizontal and vertical perspectives.


For outdoor LED advertising display, elliptical luminous tube or patch light emitting tube is generally used. The elliptical luminous tube has the characteristics of small angle and high brightness, and the vertical viewing angle of the patch light emitting tube is much larger than that of the elliptical tube, but its brightness is smaller than that of the elliptical luminous tube. From the user's point of view, the light pipes of different viewing angles should be selected according to the audience surface of the LED display and the surrounding light environment.


For indoor LED display, because of its low brightness requirements, the audience is generally wider, so the SMD tube is the best choice.


Small-sized LED chips are usually packaged in small angles in order to increase brightness. Large size does not require a small angle package because it does not require such high brightness. Therefore, high angle, high brightness and low current are the best.

Circuit design part

The design and materials of the circuit board play an important role in the stability and display effect of the LED display. There are mainly the following requirements:


1. Requirements for materials: PCB thickness, generally 1.6mm thickness; Material: FR-4 fiberglass board, copper foil thickness: The thickness of copper foil has a negligible effect on the heat dissipation of PCB board and the stability of the circuit. The normal copper foil thickness is 35um (1Oz).


2, a few key points in the design: connectors, connectors refers to the connection between the module and the module, there are two main types of use on the market, one is the horn, the other is the row needle. The advantage of the horn is that it can catch the cable through two card positions, and it is not easy to cause the failure caused by the connector problem; for the choice of electrolytic capacitor and tantalum capacitor, tantalum capacitor is undoubtedly the first choice for the occasion requiring long life. Electrolytic capacitors are preferred when low prices are required.

Automated production equipment

Most of the LED display is electronic components, and static electricity has a very serious hazard to electronic components. Sometimes static electricity directly penetrates the components to damage them. Sometimes it does not directly penetrate, but leaves hidden dangers and side effects. That is, the components are damaged after using them for a while.


For the treatment of artificial static electricity, people think of a lot of methods, including wearing an electrostatic ring, wearing a static clothes, using a clean room and so on. In fact, the most effective way is to avoid manual contact with electronic components, and the use of automated equipment achieves this goal.

Average power consumption

The square power consumption refers to the power consumption generated by the LED display of one square meter. The unit of electricity we usually say is watts/hour. For example, the power consumption of a square meter LED display is 300 watts, and this display consumes 300 watts/hour of electricity per square meter per hour, which is what we often call 0.3 kWh. The power consumption of LED displays generally has two indicators, one is the maximum power consumption, and the other is the power consumption. The maximum power consumption refers to the power consumption of the maximum brightness of the LED display. How to use the eyes to distinguish the maximum power consumption?


The method is very simple: look at the number of power sources behind the cabinet, multiply the maximum power of each power supply, and calculate the maximum power consumption of the square meter according to the size of the cabinet. There are two types of power supplies, 200W and 300W.

Small indoor spacing: low light and high gray

Low light and high gray, the specific explanation is: when the brightness of the small-pitch LED display is in the range of 100 cd/O-300 cd/O, the gray level of the display screen is not lost, or the degree of gray loss is difficult to detect by the human eye. Within the scope.


Low-light and high-ash will be one of the key factors to distinguish the quality of small-pitch LED display products. For small-pitch products, the display screen can reduce brightness without losing grayscale and image quality. In other words, only the low-gloss, high-gray small-pitch LED display is a good product that meets the user's requirements and has competitive strength.


Under the dark environment of the human eye, close-up, long-time gaze at high-brightness small-pitch LED displays. The high brightness of LEDs often makes people feel glaring, and even causes sore eyes, tears and decreased vision. Therefore, the brightness of the LED display is too high, which will bring visual fatigue to the users of indoor applications, and even serious damage may cause irreparable human eye damage! It can be said that the brightness of the small-pitch LED display is definitely not as high as possible, and its brightness must be lowered. A large number of tests have shown that the brightness range of the LED display is controlled in the brightness range of 100 cd/O-300 cd/O, and the human eye feels comfortable.


But instead of directly adjusting the brightness of the display, this problem can be solved. Because the conventional LED display has the characteristics of low brightness and low gray, that is to say, the brightness of the display is reduced, accompanied by the loss of the gray level of the picture.


Source: Electronic Products World



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