a good full-color led display must be adapted to different temperatures, different weather, and can be used normally in various occasions such a stage led concert led display and waterproof outdoor led video wall. it also has a good effect for far and near light. especially in large concerts, special effects light should be exceptional, but sometimes we will find the brightness of led. different, what is the reason for the inconsistency of the brightness of full-color led display? based on years of experience, the author summarizes the following three factors which can lead to the inconsistency of the brightness of full-color led display.
1. luminescent elements
the luminous elements of full-color led display screen, namely led light-emitting tubes, are inevitably different in brightness during the production process. but the countermeasure adopted by the manufacturers of led electronic display screen is to classify after production. the smaller the brightness difference between the adjacent two gears, the better the consistency, but the lower the yield and the higher the inventory will be. therefore, each manufacturer controls the brightness difference between two adjacent gears at 20%.
2. driving elements
the driving elements of full-color led display are usually constant-current driving chips, such as mbl5026. these chips include 16 constant-current drive outputs, which can be set by resistance. the output errors of the same chip are controlled within 3%, while the output errors of different chips are controlled within 6%. it is normal that 25% brightness errors occur among the pixels of the full-color led display. if the led light emitting tube is not a full-color led display of the same level and type, the brightness errors will rise to more than 40%.
in addition, it is worth noting that the inconsistent brightness of full-color led display screen is the fundamental reason for the formation of flower screen. it can not be corrected by post-proofreading equipment, as long as it is achieved by the production and manufacturing process of led display manufacturers. so if you buy a screen with inconsistent brightness, please contact your service provider or manufacturer to solve the problem.
3. the display screen is mixed with material in the production process, and different batches of dot matrix are used.
how to solve the color difference of led electronic display screen?
the first method is to change the current flowing through the led. generally, the continuous working current of the led tube is about 20 ma. except for the saturation of the red led, the brightness of other leds is basically proportional to the current flowing through.
the second method is to use the visual inertia of the human eye and pulse width modulation to achieve gray level control, i.e. periodically changing the light pulse width (duty cycle). as long as the cycle of repeated lighting is short enough (i.e., the refresh frequency is high enough), the human eye can not feel the fluorescent pixels shaking. because pulse width modulation is more suitable for digital control, almost all led electronic display screens use pulse width modulation to control gray level in today’s computer-based and led display content.
