In military applications, Night Vision Devices (NVD) are developed with the ability to provide a clear image thanks to the contribution of light coming from external sources such as stars, moon or artificial light of the cities. While choosing NVDs, a lot of important performance parameters need to be considered and particularly the FOM because it is used to determine the overall performance of the Image Intensifier Tube (IIT) and is calculated as a product of the IIT resolution by the Signal-to-Noise Ratio (SNR).

• The SNR typically defines how much system noise interferes with the image.
• Limiting resolution measured in line pairs per mm (lp/mm) refers to contrast allowing to gives more details

The phosphor screen of the Image Intensifier Tube (IIT) converts the electron avalanche from the microchannel plate back into photons, resulting in the green image that has become the signature view in night vision technology.

White phosphor, or P45, provides excellent recognition and has similar decay time properties as the P43 (green) phosphor. In night vision, there are no « lab » performance differences between P43 & P45. Furthermore, during trial of soldiers, no combat effectiveness difference was found. That’s why phosphor color is often a personal preference, the most important criteria being for the operator to have as less eye fatigue as possible.

Black spots are cosmetic blemishes that may originate from fixed tiny particles inside the Image Intensifier Tube (IIT) or in the fiber optic of the screen. Small size black spots are inherent to the manufacturing process and do not affect the performance or reliability of the device. Black spots can be acceptable as long as they don’t interfere with the viewing of the image to be observed and therefore specifications of tubes should be fine-tuned to match the constraints of the end-use application.

The IIT is sensitive to light if you expose this device to daylight such as sunlight, but also cloudy skies or direct light such as car headlights. So you will damage the night vision system. More especially, using an IIT when bright light hits the photocathode might seriously damage the photocathode itself. The key to avoid any damage it’s to systematically cover the night vision device (NVD) with their protective caps even if the NVD is off, raised on the helmet.

Reducing the load on a soldier is a constant challenge. We can notice a real evolution concerning the size and weight of our image intensifier tubes (IIT). We talk about SWaP: Size Weight and Power.

Reduction of SWaP contributes to enhance the efficiency and effectiveness of armed forces. Night vision devices that are designed around the 16mm IIT offer the tremendous advantage of having the same level of performance as those based upon the 18 mm tube, but with significantly reduced weight.
 

Photonis offers the highest quality of image intensifier tubes for a wide range of night vision devices which support specific requirements, environments, applications and missions: binocular goggle, monocular goggle, panoramic goggle, clip-on weapon sights, etc.

Photonis image intensifier tubes are made in Europe (Brive-La-Gaillarde, in France and Roden, in the Netherlands). That’s why they are ITAR free: The International Traffic in Arms Regulations (ITAR) is a set of U.S. federal government regulations used to control the import and export of objects and services related to national defense. 
 

In night vision, we have defined 5 different light levels from 1 (full moon) to level 5 (overcast starlight) The better the image intensifier tube, the better the image quality in low light conditions.

Night vision is the ability to operate safely in night or in any environment under low light conditions. Whereas, infrared imaging products, such as thermal (LWIR) or Shortwave Infrared (SWIR) sensors, are optimized for day-through-night lighting conditions and support surveillance & security applications, industry & research projects, and mobile use.  

First of all, photons (light) are converted into electrons by the photocathode. Then, they are accelerated through an electrical field and hit the microchannel plate walls to generate secondary electrons that in turn will generate more electrons into what is called an « electron avalanche ». Then, multiplied secondary electrons are accelerated through an electrical field, hit the phosphor screen layer and are converted back into light. Finally, the image is projected through the eye-piece of the night vision device.