Backlight Lifetime (L70) Estimator
LED backlight brightness fades with temperature and time. Enter the rated lifetime and your real operating temperature to estimate when the backlight drops to 70 % of its initial brightness (L70).
Model: L = Lrated × 2(Trated − Top)/10 — the classic rule that LED lifetime halves for every 10 °C rise. Real degradation also depends on drive current and duty cycle; treat the result as a planning figure.
FAQ
What does L70 mean for a display backlight?
L70 is the operating time after which the backlight has faded to 70 % of its initial brightness. Most industrial TFT LCD modules quote 30,000 to 70,000 hours to L70 at a reference temperature.
How does operating temperature affect LED lifetime?
As a planning rule, every 10 °C rise in LED junction temperature roughly halves the lifetime. A 50,000-hour rating at 25 °C becomes roughly 12,500 hours at 45 °C — hence derating and duty-cycle control matter in sealed enclosures.
Can I extend backlight lifetime in the field?
Yes. Reduce backlight current or use ambient-light-based dimming, improve airflow or heat sinking, and avoid running at 100 % brightness continuously. Many of our modules support PWM dimming for exactly this purpose.
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