As a media of publicity, LED display screen appears frequently in our life, and the demand for maintenance identification materials relative to LED electronic display screen is also increasing. Let's discuss how to identify the brightness of LED electronic display screen.First, let's understand what is the brightness of LED electronic display:The brightness of LED light-emitting tube refers to the intensity of light emitted by the light-emitting body, which is called light intensity and expressed by MCD. The luminous brightness of LED screen is a comprehensive index, which refers to the comprehensive index of the total luminous amount (luminous flux) of all LED modules in unit volume and the illuminance at a certain distance.
Brightness of LED display screen: the unit of luminous intensity brightness per unit area in a given direction is CD / m2.The brightness is directly proportional to the number of LEDs per unit area and the brightness of the LED itself. The brightness of LED is directly proportional to its driving current, but the service life is inversely proportional to the square of its current, so the driving current cannot be excessively increased in order to pursue brightness. Under the same point density, the brightness of LED display screen depends on the material, packaging form and size of LED chip. The larger the chip, the higher the brightness; Conversely, the lower the brightness.So what are the brightness requirements for the screen body?
General brightness requirements are as follows:(1) Indoor LED display: 800cd / m2(2) Semi indoor LED display screen: 2000cd / m2
(3) Outdoor LED display (south facing north): 4000cd / m2(4) Outdoor LED display (facing south): 8000CD / m2The quality of LED light-emitting tubes sold in the market is uneven, and most of the brightness can not be guaranteed. The phenomenon of shoddy goods deceives consumers. Most people do not have the ability to identify the brightness of LED light-emitting tubes. Therefore, businesses say that the brightness is the brightness. And it is difficult to distinguish with the naked eye, so how to identify it?
1 How to identify the brightness of LED electronic display screen1. Make a 3V DC power supply convenient for connecting light-emitting diodes, preferably made of batteries. Two button batteries can be used, which are installed in a small plastic tube and lead out two probes as positive and negative output. The tail end is directly made into a switch with shrapnel. When in use, the positive and negative probes correspondingly contact the positive and negative pins of the LED, press and hold the switch at the tail end, and the LED is powered on.2. Secondly, a simple light measuring device is composed of a photoresist and a digital multimeter. Two thin wires are led out of the photoresist and directly connected to the two probes of the digital multimeter. The gear of the multimeter is placed at 20K (depending on the photoresist, try to make the reading accurate). Note that the measured value is actually the resistance of the photoresist. Therefore, the brighter the light is, the smaller the value is.
3. Take an LED and light it with more than 3V DC. The light emitting head is facing and close to the photosensitive surface of the connected photosensitive resistor. At this time, the multimeter will read to distinguish the luminous brightness of the LED.2 Brightness discrimination level refers to the brightness level between the darkest and whitest images that can be distinguished by human eyes.
The gray level of LED electronic display screen is very high, which can reach 256 or even 1024. However, due to the limited sensitivity of human eyes to brightness, these gray levels can not be fully recognized. In other words, many people with adjacent gray levels may look the same. And eye discrimination varies from person to person. For the display screen, the more the human eye recognition level, the better, because the displayed image is for people to see after all. The more brightness levels that human eyes can distinguish, the larger the color space of the display screen, and the greater the potential to display rich colors. The brightness identification level can be tested with special software. Generally, the display screen can reach more than level 20, which is a better level.
3 Requirements for brightness and visual angle:The brightness of the indoor full-color LED display screen should be more than 800cd / m2, and the brightness of the outdoor full-color display screen should be more than 1500cd / m2 to ensure the normal operation of the display screen, otherwise the displayed image will not be seen clearly because the brightness is too low. The brightness is mainly determined by the quality of LED die. The size of the visual angle directly determines the audience of the LED display screen, so the larger the better. The viewing angle is mainly determined by the die package.It is very necessary to determine the brightness of LED electronic display screen. At present, the brightness requirements of urban bright LED display screen, or new regulations are issued. If the brightness of LED screen is too high, it will cause trouble to nearby residents. In order to avoid adverse reactions, businesses need to have relevant professional knowledge when customizing and maintaining LED displays.
The above is about how to identify the real brightness index brightness of LED electronic display screen. I hope it will help you. In addition, the brightness of LED display screen is not the bigger the better, but the appropriate brightness will achieve unexpected results according to the use demand.