PWM can’t damage LED

Many engineer ask me a question that use PWM to drive LED whether LED will be affected .
First LED is diode that it can achieve rapid switch(The application of quick switch technology in LED). which is incomparable to other component .
Hence, just only converted power supply to constant current source, then with adjust pulse width way to change the bright of LED. the way call PWM(pulse width modulation ). suppose the cycle of pulse as tpwm and width of pulse as ton, that duct cycle as ton/tpwm. adjust the duct cycle of constant current pulse can change the LED bright . so You trust to use the PWM.