Some parameter knowledge about the Gen2+ night vision image intensifier tube

(1) Image intensifier tubes vary in size

The image intensifier tubes of Gen 2+ night vision devices come in different sizes, with common specifications being 16mm, 18mm, and 25mm. 25mm is a large tube. The large tube is cost-effective, cheaper and more affordable, and the price of the corresponding large tube night vision device is also much more affordable. The price of small-tube night vision goggles is higher, about 45% higher than the price of large-tube night vision goggles.

(2) There are high and low resolutions of image intensifier tubes

One of the important parameters corresponding to the image intensifier tube of the Gen 2+ night vision device is the resolution. Not only do image intensifier tubes of the same size and specification have different resolutions, but night vision goggles of different specifications also have different resolutions. But generally speaking, the resolution of small-tube night vision intensifier tubes is higher than the resolution of large-tube night vision intensifier tubes. Common resolutions of image intensifier tubes include 36lp/mm, 38lp/mm, 40lp/mm, 45lp/mm, etc. It needs to be explained that the resolution of image intensifier tubes is divided into center resolution and edge resolution. Normally, The lower center resolution is higher than the edge resolution.

(3) Type of cathode surface of image intensifier tube

The photocathode is a device used to convert weak light into weak current. It is located in the image intensifier tube. Its sensitivity directly affects the brightness of the night vision device. The first- and second-generation night vision devices use poly-alkali photocathode, and the third-generation night vision device uses a revolutionary gallium arsenide (GaAs) photocathode, which is more than twice as sensitive as the second-generation night vision device and has a brighter picture.

The cathode surface type of the Gen 2+ night vision device image intensifier tube is S25, and the cathode surface type of the Gen 3 night vision device is GaAs. This is a very important parameter to distinguish between Gen 2+ night vision goggles and Gen3 night vision goggles. It mainly depends on the cathode surface type of the image intensifier tube.

(4) The fluorescent screen of the imaging tube determines the imaging color

The fluorescent screen is a glass plate coated with fluorescent agent, located in the image intensifier tube. The fluorescent agent emits light after being hit by electrons. It is a device that converts electric current amplified tens of millions of times into visible light. Fluorescent screens have different colors, green ones include P22 and P43, and white and bluish ones include P45 (so-called white phosphorus tubes, but in fact white phosphorus tubes are bluish). It should be noted that the performance of the fluorescent screen has an impact on the brightness and imaging sharpness of the night vision device.

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