As a medium of publicity, LED display screens appear frequently in our lives, and the demand for maintenance identification information relative to LED electronic display screens has also increased. Let us discuss how to identify the brightness of the LED electronic display.
First, let's understand what is the brightness of LED electronic display:
The brightness of the LED light-emitting tube refers to the intensity of the light emitted by the luminous body, which is called light intensity, and is expressed in MCD. The luminous brightness of the LED screen is a comprehensive index, which refers to the comprehensive index of the total luminous flux (luminous flux) of all LED modules per unit volume and the illuminance at a certain distance.
LED display brightness: In a given direction, the luminous intensity per unit area. The unit of brightness is cd/m2.
The brightness is proportional to the number of LEDs per unit area and the brightness of the LED itself. The brightness of an LED is proportional to its drive current, but its lifetime is inversely proportional to the square of its current, so the drive current cannot be increased excessively for the sake of brightness. At the same point density, the brightness of the LED display depends on the material, packaging and size of the LED chip used. The larger the chip, the higher the brightness; conversely, the lower the brightness.
So what are the brightness requirements of the ambient brightness for the screen?
The general brightness requirements are as follows:
(1) Indoor LED display: >800CD/M2
(2) Semi-indoor LED display: >2000CD/M2
(3) Outdoor LED display (facing north): >4000CD/M2
(4) Outdoor LED display (facing south): >8000CD/M2
The quality of LED light-emitting tubes sold in the market is uneven, and most of the brightness cannot be guaranteed. Consumers are deceived by shoddy phenomenon. Most people do not have the ability to distinguish the brightness of LED light-emitting tubes. Therefore, merchants say that the brightness is the same as the brightness. And it’s difficult to distinguish it by naked eyes, so how to identify it?
- Do it yourself to make a 3V DC power supply that is easy to connect to the light-emitting diodes, preferably using batteries. You can use two button batteries, put them in a small plastic tube and lead out two probes as positive and negative outputs. The end is directly made into a switch with shrapnel. When in use, the positive and negative probes correspond to the positive and negative of the light-emitting diode. On the negative pin, press and hold the switch at the end, and the luminous tube will emit light.
- Secondly, combine a photoresistor and a digital multimeter to form a simple light metering device. Lead the photoresistor with two thin wires and connect them directly to the two pens of the digital multimeter. The multimeter is placed at the 20K position (depending on the photoresistor, Try to make the reading as accurate as possible). Note that the measured value isn actually the resistance value of the photoresistor, so the brighter the light, the smaller the value.
- Take an LED light-emitting diode and use the above 3V direct current to light it. The light-emitting head is facing and close to the photosensitive surface of the connected photoresistor. At this time, the multimeter reads to distinguish the brightness of the LED.
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 cannot be fully recognized. That is to say, it is possible that many adjacent levels of gray scale human eyes look the same. Moreover, the distinguishing ability of eyes varies from person to person. For the display screen, the higher the level of human eye recognition, the better, because the displayed image is for people to see after all. The more brightness levels that the human eye can distinguish, the larger the color space of the display, and the greater the potential for displaying rich colors. The brightness discrimination level can be tested with special software. Generally, the display screen can reach 20 levels or more, even if it is a good level.
The brightness of the indoor full-color LED display must be above 800cd/m2, and the brightness of the outdoor full-color display must be above 1500cd/m2 to ensure the normal operation of the display, otherwise the displayed image will not be clear because the brightness is too low. The brightness is mainly determined by the quality of the LED die. The size of the viewing angle directly determines the audience of the LED display, so the larger the better. The viewing angle is mainly determined by the die package.
It is very necessary to determine the brightness of the LED electronic display. The current requirements for the brightness of the LED display in urban lighting, or new regulations, the brightness of the LED screen is too high, it will cause trouble to nearby residents. In order to avoid bad reactions, this requires businesses to have relevant professional knowledge when customizing and maintaining LED displays.
The above is about how to identify the true brightness index brightness of the LED electronic display. I hope it will be helpful to everyone. In addition, the brightness of the LED display is not the bigger the better, but according to the needs of the use, the appropriate brightness will be unexpected. Effect.