The effect of 850nm and 940nm on the wavelength of infrared transmitting tube in the spectrum of night vision instrument

The infrared emitting tube composed of infrared light-emitting diode is an important part of the infrared pair tube. It is made of gallium arsenide PN junction, and the PN junction is excited by injecting current into the PN junction through forward bias. The spectral power distribution is between 830~950 nm. LED is displayed as a positive temperature coefficient, the higher the current, the higher the temperature, the greater the current, the greater the LED power and current, but when the positive current exceeds the maximum rating, the LED transmission power decreases instead.

What's the difference between 850nm and 940nm?

At present, the market of red light LED is also called infrared emission tube or red light, wavelength mainly 850,940NM, of course, there are 880NM, but 880 is not commonly used, also called red light LED:

850 or 940 refers to the wavelength of LED chip emission, the unit is NM, both belong to infrared light, the first performance is different wavelength.

Generally speaking, the higher the wavelength value, the lower its 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. The VF value of 940 is about 1.10-1.25V, of course, the VF value will be different with different current.

850 red explosion, 940 no red explosion, the so-called red explosion refers to the red light in the work of the chip visually visible red dot, so if you need to hide the case, the use of 940 is a good choice, but some customers will use black colloidal 850 to hide the red explosion, but pay attention to the red explosion or visible.

The radiation intensity of 850 is about two to three times higher than the radiation intensity value of 940, and the brightness will be higher if the radiation intensity value is higher.

In the incoming material test, 850 can be directly lit with 1.5V battery to judge, but 940 needs to use a mobile phone or camera to judge whether it is normal.

Under the same current condition, the power consumption of 940 is smaller than that of 850 due to the reduced voltage. Therefore, the current sustained by a chip of the same size will be larger than that of 850.

At present, 940 is rarely used as an infrared light source. It is generally used for pulse working state, such as remote control. Because the requirements of ordinary remote control are not high, the 940 used is impossible to be used for camera infrared light source.

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

1, wavelength: 808nm, suitable for medical devices, space optical communication, infrared lighting, solid laser pump light source;

2, wavelength: 830nm, suitable for highway automatic card swiping system (night vision system is the best, you can see a little red light on the tube core, the effect is better than 850nm);

3, wavelength: 840nm, suitable for camera, color multiplier infrared waterproof;

4, wavelength: 850nm, suitable for camera, digital photography, monitoring, building intercom, burglar alarm, infrared waterproof;

5, wavelength: 870nm, suitable for shopping malls, intersection cameras;

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