The relationship between About IR led strip 940nm frequency and 38khz IR led strip 940nm frequency not in the infrared range?
Check the lectromagnetic spectrum

and infrared frequencies is above 3*10^11, also is 300GHZ frequencies above.but the infrared remote control frequency were 38kHz. this frequency is not within the infrared range? How is it?How to return a responsibility?The simplest and most intelligible answer to this question is infrared is a light, and light has wave-particle duality, that in itself can have wave infrared features,Since there are characteristics of waves, it has a periodic (frequency).with waves properties suited for high-tech applications，such as Infrared control. Reflection, it was said above,300GHZ should refer to this frequency. and 38KHZ carrier frequency is modulated infrared involving radio,, involves to the radio, I suggest an alternative strategy（infrared on-off time） to comprehend. infrared appear 13US, and then disappear 13US, again 13us, then disappear 13US. equivalent period 26us(that is the frequency for 38kHz). Only in this way integration of infrared receiving head can receive the signal,if deviation 38KHZ too much, can not receive a signal.