night vision Infrared emission tube wavelength, the role of 850nm and 940nm

The infrared emission tube that uses infrared light-emitting diodes to form the illuminant is an important part of the infrared pair tube. It is made of gallium arsenide to make a PN junction, and injects current into the PN junction through forward bias to excite infrared light. Its spectral power distribution is in Between 830 and 950 nanometers. The LED shows a positive temperature coefficient, the greater the current, the higher the temperature, the greater the current, the greater the power and current of the LED, but when the forward current exceeds the maximum rated value, the emission power of the LED will decrease instead.
        What is the difference between 850nm and 940nm infrared emission tubes?

At present, the infrared light LEDs on the market are also called infrared emission tubes or infrared lights. The wavelengths are mainly 850, 940NM, and of course 880NM, but 880 is not commonly used, and it is also called infrared light LED:

850 or 940 refers to the wavelength emitted by the LED chip, the unit is NM, both belong to infrared light, and the first performance is the difference in wavelength.

Generally speaking, the higher the wavelength value, the lower the forward voltage drop VF value will be under the same current condition. Under the condition of 20MA current, the VF value of 850 is about 1.35-1.55V; while the VF value of 940 is about 1.35-1.55V. Between 1.10-1.25V, of course, the VF value will be different with different currents.

The 850 has a red burst, but the 940 has no red burst. The so-called red burst refers to the visible red dots on the chip when the infrared light is working. Therefore, if concealment is required, it is a good choice to use the 940, but some customers will Use black colloid 850 to cover up the red burst, but if you pay attention, the red burst is still visible.

The radiation intensity of 850 is about 2-3 times higher than that of 940. If the radiation intensity value is high, the brightness displayed will be higher.

When testing incoming materials, the 850 can be judged by directly lighting it with a 1.5V battery, but the 940 needs to use a mobile phone or camera to judge whether it is normal.

Under the same current conditions, due to the voltage drop of the 940, its power consumption will be smaller than that of the 850, so the chip with the same size can withstand a larger current than the 850.

At present, 940 is rarely used as an infrared light source. It is generally used in pulse working conditions, such as remote controls. Because the requirements of ordinary remote controls are not high, it is impossible to use 940 as a camera infrared light source.

According to the characteristics of infrared LED lamp beads, it can be used more widely according to different wavelengths:

1. Wavelength: 808nm, suitable for pump light source of medical equipment, space optical communication, infrared lighting and solid laser;

2. Wavelength: 830nm, suitable for automatic card swiping system on highways (night vision system is the best, you can see a little red light on the die, the effect is better than 850nm);

3. Wavelength: 840nm, suitable for camera, color zoom infrared waterproof;

4. Wavelength: 850nm, suitable for cameras, digital photography, monitoring, apartment intercom, anti-theft alarm, infrared waterproof;

5. Wavelength: 870nm, suitable for cameras in shopping malls and intersections;

6. Wavelength: 940nm, suitable for remote control, such as the remote control of household appliances.