Nov. 06, 2020< Back to list
There are many types of LED displays on the market, and the price difference is huge. Meanwhile, LED displays are high-value products, so it is very important to learn to choose high-quality displays. Consumers can judge the display quality from the following aspects.
1. Maximum brightness
Maximum brightness refers to the brightness of each primary color of the LED display at the highest grayscale and highest brightness. In short, it is the brightness measured by the light gun in the normal direction when the screen is set to white 255 by using the software.
For indoor LED displays, due to the weak ambient light, 800CD brightness is sufficient in theory.
For outdoor LED displays, the maximum brightness is different in different environments. In places with strong ambient light, the brightness of the led display should be higher to allow the masses to see the video. In theory, a brightness of more than 5500nits is enough.
When we see that the color of the image on the display is inconsistent with the material, then our picture is seriously distorted, which is related to the color temperature of the white balance of the LED display.
When the human eye directly looks at the display screen, the white balance color temperature value is between 6500 and 8000K. And if it is a display screen used by a TV station for broadcasting, the actual color temperature of the screen needs to be adjusted to about 5500K, so that the picture on the display screen is normal after the camera is recorded and broadcasted.
3. Refresh rate
The refresh rate refers to the number of times the electron beam repeatedly scans the image on the screen.
The higher the refresh rate, the better the stability of the displayed image (picture).
The lower the refresh rate, the more flickering and shaking the image, and the faster the eyestrain. Generally speaking, if the refresh frequency can reach above 80Hz, the image flicker and jitter can be eliminated, and the eyes will not be too tired.
At the same time, high refresh can improve the brightness and color fidelity of the display. It can be detected with a digital camera. If it is high refresh, the picture taken by the camera is very clear, without snowflakes and scan lines. This indicator is especially important when renting screens and TV broadcasting.
4. Circuit design part
The design and materials of the circuit board play a vital role in the stability and display effect of the LED display. There are mainly the following requirements:
4.1. Material requirements: PCB thickness, generally 1.6mm thickness; Material: FR-4 fiberglass board. Some manufacturers may use FR-2 paper substrates in order to reduce costs;
Copper foil thickness:
The thickness of the copper foil has a non-negligible effect on the heat dissipation of the PCB board and the stability of the circuit. The normal copper foil thickness is 35um, and some manufacturers will use 18um copper foil thickness to charge it as a shoddy;
So how do you distinguish it as a consumer?
An empty PCB can be distinguished by weight. Normally, the heavier the better.
4.2. Design requirements: connectors.
Connectors refer to the connection between the module and the module. There are currently two main types on the market: horns and pin headers. The advantage of the horn is that the cable can be jammed by two card positions, and it will not easily cause failures caused by connector problems.
5.Square power consumption
The square power consumption refers to the power consumption of an LED display with an area of one square meter, in watts, and 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 each square meter of the display will consume 300 watts per hour per hour, which is what we often call 0.3 kilowatt-hours of electricity.
There are generally two indicators for the power consumption of an LED display, one is the maximum power consumption and the other is the power consumption in use.
Maximum power consumption refers to the power consumption of the LED display at maximum brightness.
How to distinguish the maximum power consumption?
The number of power supplies behind the box is multiplied by the maximum power of each power supply, and combined with the size of the box, the maximum power consumption per square meter can be calculated. There are two general power supplies, 200W, and 300W power supplies.
The power consumption refers to the power consumption when advertising videos, texts, and pictures are played. Since the power consumption is directly related to the content being played, it is difficult to have an exact value. According to our experience, the general square power consumption is 1/3 of the maximum power consumption. Lower power consumption means lower cost and less heat. The amount of heat depends on the current, which directly affects the service life and stability of the display.
Energy-saving LED displays to use four 200-watt power supplies per square meter. Because the effective output of the power supply is basically 85%, the maximum power consumption will not exceed 680 watts per square meter.
6. Indoor small spacing: low brightness and high gray
Low brightness and high gray, the specific explanation is: when the brightness of the small-pitch LED display is 100-300 nits, the gray level of the display screen is not lost, or the gray level loss is in the range that is difficult to detect by the human eye.
Low brightness and high gray will be one of the key factors to distinguish the high quality of small-pitch LED display products. For small-pitch products, the competition for LED displays will no longer be to compare whose brightness is high but to compare whose brightness is low. A high-quality display is the only way to reduce brightness without losing grayscale and image quality. In other words, only a small-pitch LED display with low brightness and high gray is a good product that meets user requirements and has competitive strength.
In a dark indoor environment, human eyes may look at high-brightness small-pitch LED displays at close range and for a long time. The unique high brightness of LEDs often makes people feel dazzling, and even causes eye soreness, tearing, and reduced vision. Therefore, if the brightness of the LED display is too high, it will bring visual fatigue to the indoor users, and may even cause irreparable eye damage!
Therefore, the brightness of the small-pitch LED display is definitely not as high as possible. A large number of tests have shown that the brightness range of the LED display is controlled at 100-300 nits, and the human eye feels more comfortable.
But not directly adjusting the brightness of the display can solve this problem. Because, the conventional LED display screen has the characteristics of low brightness and low gray, which means that the brightness of the display screen will be reduced with the loss of the grayscale of the picture.