Image Intensifier

An image intensifier (abbreviation: II or I²) is an electro-optical component that can produce an intensified monochrome image on a phosphor screen from a cone of incoming light, intended to intensify the signal beyond what optics and digital sensors are capable of.

In the field of night vision, image intensifier refers to image intensifier tubes which are miniaturized image intensifiers (usually in tubular shape) that form the core component of any night vision device.

Image intensifier tubes are inserted into a housing that otherwise only provides optics, power supply, and protection of the sensitive component. Many formats of image intensifier tubes are designed to be exchangable with limited tooling and know-how, originally intended to allow armies to replace damaged image intensifier tubes by an engineer during deployment.

Generations

Generation 0

Generation 0 was invented in 1929 by a hungarian scientist in the UK. First uses where in World War II by the Germans, later the Soviets and the Americans.

Gen 0 tubes dont have any or only very low gain of a around 10 and thus rely on strong Ir ilumination.

Examples of devices

Vampir

M2 & M3 Sniperscope

PNV57A

Generation 1

Generation 1, developed and patented in the 1960s, improved greatly the Gain to around 1000. This enabled the use of Gen 1 devices under Moonlight conditions without the use of IR ilumination.

Later developments included Gen 1+. There the glass in the body was replaced with ceramic. The gain was further improved.

Some devices used multible tubes in a cascade configuration which leads in strong Gain improvements of up to 100,000.

Examples of devices

AN/PAS 2 Starlight

Armasight Spark

PNV57H

also used in most cheap consumer devices

Generation 2

The generation 2 was developed in thee 1970s and was the 1st generation wich uses a Microchannel Plate (MCP). During this time, due to drastic inovations in the semiconductor space, the first widespread integration of the PSU with the tube in a single, modern package appears. The Microchannel Plate (MCP) increased the gain imens.

Gain average around 20k.

Generation 3

Photocathode is made using gallium arsenide and MCP is coated with an ion barrier film to prolong the tubes functional life.

Gain averages between 30k to 50k.