How to judge the real brightness index of LED screen
How to identify the brightness of LED display
1. Make a 3V DC power supply that is easy to connect to the LED by yourself, preferably with a battery. Two button batteries can be used, which are installed in a small plastic tube and lead out two probes as positive and negative output, and the tail end is directly made into a switch with shrapnel. When in use, the positive and negative probes correspond to the positive and negative contacts of the LED. Negative pin, press and hold the switch at the end, the light-emitting tube will emit electricity.
2. Secondly, combine a photoresistor and a digital multimeter to form a simple light metering device, lead out two thin wires from the photoresistor, and connect them directly to the two test pens of the digital multimeter. The multimeter gear is placed at the 20K position (depending on the photoresistor, Try to make the reading accurate), note that the measured value is actually the resistance value of the photoresistor, so the brighter the light, the smaller the value.
3. Take an LED light-emitting diode and light it with the above 3V direct current. The light-emitting head is facing and close to the light-sensitive surface of the connected photoresistor. At this time, the multimeter will display a reading to distinguish the brightness of the LED.
The brightness discrimination level refers to the brightness level of the image that can be distinguished by the human eye from the darkest to the whitest.
The gray level of the LED display screen is very high, which can reach 256 levels or even 1024 levels. However, due to the limited sensitivity of the human eye to brightness, these gray levels cannot be fully recognized. That is to say, many adjacent levels of grayscale may look the same to the human eye. And the ability of the eyes to distinguish is different for each 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 the human eye can distinguish, the greater the color space of the display, and the greater the potential for rich colors. The brightness discrimination level can be tested with special software. Generally, if the display screen can reach level 20 or above, it is considered a good level.
Requirements for brightness and viewing angle:
The brightness of the indoor full-color LED display should be above 800cd/m2, and the brightness of the outdoor full-color LED display should be above 1500cd/m2 to ensure the normal operation of the display, otherwise the displayed image will be unclear because the brightness is too low. The size of the brightness is mainly determined by the quality of the LED die. The size of the viewing angle directly determines the number of LED display audiences, so the bigger the better. The viewing angle is mainly determined by the die package.
It is very necessary to determine the brightness of the LED display screen. The current brightness requirements of the LED display screen for urban lighting, or new regulations, the brightness of the LED screen is too high, which will cause trouble to the nearby residents. In order to avoid adverse reactions, this requires businesses to have relevant expertise when customizing and maintaining LED displays.