Difference between 850nm and 940nm infrared LED

At present, the infrared LED lights on the market are also called infrared emitting beads or infrared lamps. The wavelengths are mainly 850nm and 940nm. Of course, there are also 880nm, but 880nm is not commonly used, it is also called infrared LED lights. 

What is the difference between 850nm and 940nm infrared LED?

1. 850nm or 940nm are the wavelengths emitted by the LED chip, the unit is nm, both of which belong to infrared light, firstly manifested as different wavelengths.

2. Generally speaking, under the same current, the higher the wavelength value, the lower the forward voltage drop VF value. Under the condition of 20ma current, the VF value of 850nm is about 1.35-1.55V; and the VF value of 940nm is about 1.10-1.25V. Of course, the VF value will vary depending on the current.

3. There is a red burst for 850nm and no red burst for 940nm. The so-called red burst refers to the visible red dot of the chip when the infrared lamp is working, so if you need to hide it, using 940nm is a good choice, but some Customers will use black colloid to cover up the 850nm red burst, but if you pay attention, the red burst is still visible.

4. The radiation intensity of 850nm is about 2-3 times the radiation intensity of 940nm. The higher the radiation intensity, the higher the brightness.

5. When test, the 850nm can be judged by eye, using a 1.5V battery directly to power on, but the 940nm needs to use a mobile phone or a camera to judge whether it is normal.

6. Under the same current condition, due to the voltage drop of 940nm, its power consumption is less than 850nm. Therefore, the current of 940nm of the same size will be a little larger than that of 850nm.