Currently, the mainstream ones are 2nd generation + night vision devices and 3rd generation night vision devices. So what is the essential difference between these two types of night vision devices? In fact, the main difference is the image tube, also called an image intensifier or image intensifier tube.
First, let’s take a look at the parameters and indicators related to the image tube?
Parameters related to the night vision image tube retain resolution, sensitivity, signal-to-noise ratio, brightness gain, equivalent background illumination, output brightness, brightness uniformity, working life, working voltage, effective cathode diameter, etc. Among them, resolution is the most common indicator, followed by the three indicators of sensitivity, signal-to-noise ratio, and brightness gain. The other indicators are more focused on indicators for technical engineers rather than for end users, so the rest The indicator is not common and does not appear in the product parameters.
The focus here is on resolution. The resolution index is a parameter standard for judging the quality of night vision devices of the same level. The premise here is that they are of the same level, that is, compared between 2nd generation + level or 3rd generation night vision equipment. Sometimes the resolution parameters of the 3rd generation night vision device are lower than those of the 2nd generation + night vision device. Therefore, it is not possible to determine which level the night vision device belongs to from the resolution index parameters alone.
Sensitivity is related to the brightness and contrast of the image. The signal-to-noise ratio is related to imaging noise and distortion. FOM value, calculated as clarity*signal-to-noise ratio, is used to evaluate the overall performance of night vision devices.
The material of the tube is the most critical difference
The main difference between the 2nd generation+ night vision goggles and the 3rd generation night vision goggles is the type of cathode tube. The 2nd generation+ generally uses S25, while the 3rd generation uses gallium arsenide (GaAs in English). The two types of image tubes have different capabilities for light sensitivity.
In practice, this parameter will also be reflected in the data of 2nd generation + night vision goggles and 3rd generation night vision goggles. This parameter alone can determine which level of night vision device the customer requires.
The difference in imaging effects
There are three mains tream types of imaging effect colors, namely green, yellow-green, and black and white. The difference between green and yellow-green is not very obvious. The black and white imaging effect is what is commonly called a white phosphorus tube night vision device. Each imaging color has its pros and cons, but I think green or yellow-green will have better recognition of viewing targets. Recognition is the ability to identify what object the target is. The ability to generate image clarity in extremely low light environments, the degree of distortion of the image, the ability to identify targets, viewing distance, etc. vary.
When special attention is needed, the appearance of the 2nd generation + night vision device and the 3rd generation night vision device may be exactly the same. Below you can compare which one is the effect of the 2nd generation + night vision device and which one is the effect of the 3rd generation night vision device. The two videos below are of white /Green phosphorus tube night vision devices.
