Phosphor Screen
The phosphor screen converts electrons emitted by the MCP back into visible light.
There are different phosphor types (different chemical compositions) producing various shades of light.
Commonly used phosphors are P20, P22, P31, P43 and P45.
Specifications
| Type | Composition | Wavelength (nm) | Peak (nm) | Color | Decay Time | ||
|---|---|---|---|---|---|---|---|
| from | to | typical | 90% - 10% | 10% - 1% | |||
| P43 | Gd2O 2S:Tb | 360 | 680 | 545 | 1 ms | 1.6 ms | |
| P20 | (Zn,Cd)S:Ag | 470 | 670 | 550 | 4 ms | 55 ms | |
Military use
The U.S. military adopted green P43 phosphor as a standard, taking advantage of the outstanding native ability of the human eye to recognize movement and silhouettes in green foliage. White phosphor tubes have been available since around 2010, but adoption has been slow. Photonis is still manufacturing green phosphor tubes with generally higher specifications than their white counterparts, whereas L3 and Elbit USA exclusively manufacture their best tubes with white phosphor. Most new military contracts in the US, require white phosphor tubes. Some legacy night vision devices and spare tubes for these are still contracted with green phosphor as a requirement. White phosphor is now also available for FOM limited export tubes from the US.
Civilian use
In recent years, however, an increasing number of civilian night vision users started to prefer the white phosphor P45 for various reasons. Many claim it is to reduce the eye strain from the prolonged viewing of a green image. The use of white phosphor NVG's in the 2019 video game title Call of Duty: Modern Warfare has lead to a further increase in it's popularity.
