What does “brightness decay” mean?
Every LED loses a small share of its original brightness over its lifespan – this is physically unavoidable. Manufacturers usually specify an L70 value: the operating point (in hours) at which the LED still delivers 70% of its initial brightness. For professional outdoor LEDs, this value is 50,000 to 100,000 hours – equivalent to around 11 to 22 years at twelve hours of daily operation.
Why does an LED dim over time?
The main causes are heat, UV radiation, and current density. The hotter an LED runs and the harder it is driven, the faster the semiconductor ages. This is exactly why heat dissipation is a central design criterion of professional LED walls: well-ventilated cabinets, high-quality aluminium chassis, and intelligent brightness control considerably extend the lifespan.
How your wall stays bright for a long time
- Adapt brightness to the environment – most systems are operated with a reserve that is only fully used in direct midday sun. A brightness sensor automatically reduces output at night and protects the diodes.
- Choose high-quality chips – see also LED Chip Manufacturers and Gold Wire Bonding. Brand-name chips dim considerably more slowly.
- Regular maintenance – more on this under Maintenance & Warranty.
- Recalibrate modules when needed – on large walls, after several years we re-align the individual cabinets to each other via software so that differences remain invisible.
What does this mean for planning?
We design our systems so that the required brightness is still achieved in standard operation even after years – not only at maximum output. A wall that has to run at 100% right after installation is incorrectly dimensioned. A professionally designed WALED wall typically runs between 50 and 75% – with plenty of headroom.