Lesson 17 - Gen 3 Image Intensifiers: The Core Components

In the world of thermal and night vision optics, Armasight stands as a pillar of innovation and precision. In this lesson, we're delving into the core components of these image intensifiers, unraveling the science behind the magic in plain language.

1. The Face Plate (Input Window)

Imagine the face plate as the glass window at the front of the tube. It's like a stage where the action begins. The objective lens of the system focuses the image onto this faceplate. It's the first stop in the journey of light towards creating a night vision image.

2. The Photocathode

Now, behind the scenes (inside the vacuum side of the faceplate), we have the photocathode. Think of it as the star of the show. This layer of material is like a light-sensitive sponge. When it absorbs light, it spits out electrons. In simple terms, it converts the energy of incoming photons (light) into electrons.

3. The Micro Channel Plate

Here's where the real magic happens. The Micro Channel Plate (MCP) is the heart of image intensifiers. It takes those freshly minted electrons from the photocathode and multiplies them. The MCP is a thin piece of glass with millions of tiny holes called channels. This glass has a remarkable ability: when an electron enters a channel and hits the wall, it sets off a chain reaction, and hundreds of electrons burst out. This multiplication effect is where the true image enhancement takes place.

4. The Screen (Phosphor Layer)

The screen, or the phosphor layer, is like the artist in the room. It's applied to the inside (the vacuum side) of the output optic, which we'll talk about in a moment. When electrons reach this phosphor layer, it turns them into photons, which is a fancy way of saying it makes them emit light. It's the step that lets us see the image. Traditionally, this phosphor has been green, but today, white phosphor is taking the stage. White phosphor technology offers grayscale displays that are closer to what the human eye naturally perceives in low light. This makes it great for urban environments, and it leads to less eye fatigue and faster recognition.

5. The Output Optic

The output optic, a fiber optic piece, is like a messenger. It carries the image from the phosphor screen to the other end of the fiber optic so you can actually see it. There are terms like inverting and non-inverting, which refer to this output fiber optic. Most night vision goggles require an inverting image intensifier.

6. The Body

The body is like the sturdy foundation that holds everything together. It's a series of metalized ceramic rings that create a cylinder to keep all the components in place with precision. This cylinder is essential because the image intensifier operates in a vacuum, and the body must provide a hermetic seal to maintain this environment.

7. The Power Supply

The power supply is the energy source behind the scenes. It provides power to the photocathode, MCP, and screen. It runs on a battery and provides voltages ranging from about 600 to 6500 volts. The terms gated or non-gated refer to the power supply. Most image intensifiers today have gated power supplies.

8. The Outer Housing

The outer housing is the sleek, protective covering of the image intensifier. It not only provides the final assembly for the power supply and the vacuum tube but also adheres to strict mechanical specifications for interchangeability across different manufacturers.

Remember, image intensifiers are vacuum tubes, and these components perform their magic in a vacuum environment. Understanding these core components gives you a glimpse into the remarkable technology that enables us to see in the dark and decode the secrets of the night. Armasight uses Elbit Systems of America Gen 3 Image Intensifiers, which are a testament to the marriage of science and innovation, allowing us to explore the unseen and understand the mysteries of the night.