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Differences between 850nm and 940nm IR LED

Views:0     Author:Site Editor     Publish Time: 2021-04-15      Origin:Site

What is infrared light?

The light visible to the naked eye is called visible light, and the wavelength of visible light is 380-760nm. The order of the wavelength of visible light from short to long is: purple light→blue light→cyan light→green light→yellow light→orange light→red light. Light with a longer wavelength than red light is called infrared light. Infrared rays cannot be seen with naked eyes. 

What is 850nm LED infrared light? 

The light intensity of the 850nm LED infrared in the visible part (less than 760nm) doesn't reached 0, in other words, it still emits weak visible light, and the human eye can still feel the faint light. 

850nm

What is 940nm LED infrared light? 

940nm LED infrared night vision light has a peak intensity of 940nm, which is far from the wavelength range of visible light. When the light intensity reaches 0 in the visible wavelength range, which means the minimum wavelength is higher than the visible long wavelength of 760nm. Therefore, the 940nm infrared light is invisible to the naked eye.

940nm

Differences between 850nm and 950nm LED infrared light

1. Generally speaking, the higher the wavelength value, the lower the VF value under the same voltage. Under the condition of 20MA voltage, the VF value of 850nm is about 1.35-1.55V; and the VF value of 940nm is about 1.10-1.25V. Among them, of course the VF value will be different for different voltages. 

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

3. The chip of 850nm infrared light has a visible red dot, while the main advantage of the 940nm wavelength is that the IR LED does not produce any visible light. In other words, they are completely invisible and can be used in applications that require more privacy. In fact, many people refer to it as "Covert IR". This type of IR is also useful where red light may be mistaken for a signal and cannot be used. The disadvantage of 940nm is that their efficiency is reduced by about 30-40%, and the distance of illumination is getting smaller and smaller.