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How to calculate LED display brightness ?
LED display now become very popular product for the outside advertising, event, shows and so on, and there are many people don’t know how to calculate the brightness, here give detail information for the calculation. Let’s take P12mm outdoor 1R1G1B DIP346 for example, total pixels is 6944/m2, and scan module 1/2.
And before calculation, we need know the brightness of each LED, this can be supplied by the package companies, we take the following list for example:
| Color | Red | Green | Blue |
|---|---|---|---|
| Original brightness | 1000 mcd | 2100 mcd | 400 mcd |
| Ratio | 30% | 60% | 10% |
| All with 10% | 1000/3=333 mcd | 2100/6=350 mcd | 400/1=400 mcd |
P12mm LED display with 1R1G1B, so the original brightness for each pixel is:
1x1000mcd+1x2100mcd+1x400mcd=3500mcd=3.5cd
But the original brightness is not with R:G:B=3:6:1, so it’s not in white balance. And now we need to adjust the LED brightness with 3:6:1 ratio, this ratio means: red take 30% of total brightness, blue take 60%, and Blue take 10%.
| Color | Red | Green | Blue |
|---|---|---|---|
| All with 10% | 1000/3=333 mcd | 2100/6=350 mcd | 400/1=400 mcd |
| Adjust brightness | 10%=333 mcd | 10%=333 mcd | 10%=333 mcd |
| White Balance | 30%=1000 mcd | 60%=2000 mcd | 10%=333 mcd |
| Pixel brightness | One squre meter in total: 3.333×6944=23144cd | ||
| Sq.m brightness | One squre meter in total: 3.333×6944=23144cd | ||
| 1/2 scan | 23144/2=11572cd/m2 | ||
| 20% loss | 11572×80%=9257.6cd/m2 | ||
When in 10% brightness:
Red 333mcd So we calculate based on red brightness, and cut the green and blue color, and meet the ratio:R:G:B=3:6:1. And the one pixel brightness is: 3.333cd, for P12mm with 6944 pixels each square meter, so the brightness is 23144/m2, also for P12mm LED screen, when in 1/2 scan, the brightness is also 1/2, that 11572cd/m2, and this is just theoretical value, there will be about 20% loss when use, so the final brightness is 9257.6cd/m2, or 9257.6 nit. So, did you got how to calculate the brightness finally ?
