led display screen Manufacturer

How to reasonably control the LED display brightness

 

As the LED display application in all fields become more and more widely, people for the LED display technology requirements is also more and more high. Should be in door inside and outside of the LED display in a different environment, the brightness of the required level is different also, outdoor LED display application in outdoor, the day was wide direct sunlight, then no need to that high brightness, and at night, it needs high brightness, and indoor the LED display also may according to the use of the environment and time is different, need different brightness, so the LED display brightness is how to control? Control screen brightness introduces below the two methods.

One way is to pulse width modulation (PWM), use of the human eye can feel the change of frequency, with pulse width modulation method to realize the gray control, also is cyclical change a light pulse width (i.e. occupies emptiescompared), just the repeated the light cycle short enough (i.e. refresh frequency is high enough), the human eye is not feel light pixels are shaking. Due to the pulse width modulation more suitable for digital control, so get a very wide hair negotiable use. The common method is adopted to provide LED microcomputer showing the way. Now almost all the LED screen is adopted to control the pulse width modulation of gray level.

Another is to change the current flows through LED, common LED tube allows current in 20 ma for task or so, besides red LED a saturation outside, the rest brightness LED with flow of current basically in proportion; But this adjustment method is simple, but with LED screens requirements gradually improve, also more and more does not adapt to quickly and accurately modulation, accept the a common modulation method;

LED by the control system master control box, scanning ordinary board and display control installation three major components. Master control box from the computer display card in get a screen pixel all kinds of brightness data, and then give some new deployment of scanning board, each scan as control board LED screen on several of row (column), and each row (column) LED display control signal is the way with serial transmission. There are two serial transmission display and control signals by means of: one kind is scanning board on the set control every pixel gray, scanning the board of control box in the future since the pixel luminance values stop synthesis (i.e. pulse width modulation), and then will all of the old guard of pulse signal with LED way (light is 1, not bright 0) in line with serial mode to the corresponding LED, can control the light. This way, using device less, but large quantities of serial data, because in a repeated the light cycle, each pixel in 16 level gray needs 16 pulse, in 256 under the gray level 256 pulse demand, because the device task frequency limit, ordinary can only make the LED screen do 16 level gray.

Another method is scanning the way not to serial plate each switch signals LED but a eight binary brightness values. Each LED all have a my pulse width omdulatros to control the light of time. So, in a repeated the light cycle, each pixel gray level in 16 under four pulses only ask for class of 256 under a pulse 8 gray only, which greatly increased the serial transmission frequency. In this together control LED the method can very and gray level 256 local realize gray control.

Most current LED display manufacturers are using this two control method, in order to guarantee the LED display brightness; ERALED research and development of the LED display also has brightness automatic adjustment, and other functions, can according to different environment and time display to be automatic adjust brightness.


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