Identify the brightness of the LED display method:
1, make their own hands with the battery to make a light connection to connect the 3V DC power supply. You can use two button batteries, installed in a small plastic tube and leads to two probes as positive and negative output, the end of the shrapnel made directly with a switch, the use of positive and negative probe corresponding to the contact with the light Negative pin, press the end of the switch, the luminous tube was light.
2, with a photosensitive resistor and digital multimeter into a simple metering device, the photosensitive resistor leads to two thin wires, directly connected to the digital multimeter on the two test pen, multimeter stalls placed in 20K position (depending on the photosensitive resistor, as far as possible Readings are accurate), note that the measured value is actually the resistance of the photoresistor, so the lighter the light the smaller the value.
3, take a LED light-emitting diodes, with the above 3V DC light, bright head and close to the photosensitive connection connected to the photosensitive surface, this time, multimeter readings, in order to distinguish LED luminous brightness.
Second, the brightness level of identification
Brightness discrimination level, refers to the human eye can distinguish the image from the darkest to the most white between the brightness level. LED display gray level is very high, you can reach 256 or even 1024. However, due to the sensitivity of the human eye to brightness is limited, and can not fully recognize the gray level. That is to say that many adjacent levels of gray-scale people may look the same. And the ability to distinguish eyes each person is different. For the display, the human eye recognition level is naturally the better, because the display of the image, after all, is to see people. The greater the brightness level that the human eye can distinguish, the greater the color space of the display, and the greater the potential for rich colors. Brightness discrimination level can be used to test the software, the general display can reach more than 20 even if the better level.
Third, brightness and viewing angle
Indoor full color LED display brightness to 800cd / m2 above, outdoor full color brightness to 1500cd / m2 or more, in order to ensure the normal work of the display, otherwise because the brightness is too low to see the displayed image. The brightness of the size of the LED die is mainly determined by the good or bad. The size of the visual angle directly determine the number of LED display audience, so the bigger the better. The viewing angle is primarily determined by the die package.