In this article you will learn what are the various types of night vision generation and how does night vision work - If you want to learn about these two topic then this article is must for you. Read on ...
Night vision technology has been around for quite some time now. To be more specific, this technology has been around since the Second World War. Originally, the technology was perceived to be the reserve of the military.
Over the years; however, this technology has been made accessible and available to civilians. Today, there are quite a number of devices that utilize this technology from night vision goggles to night vision binoculars and monocular.
Hunters, in particular, have found this technology to be of great benefit. But just like any other modern technology, night vision technology has undergone a number of evolutions.
The evolution of the technology can be grouped into four generations. These four generations of night vision are;
Night Vision Generation 1
The first generation of night vision technology offers basic night vision capabilities. This means that first generation devices function by amplifying existing ambient light. Most first generation devices come equipped with infrared illuminators. Due to their basic level technology, first generation devices come with some drawbacks.
For starters, most produce a high pitched whine when turned on. Secondly, these devices tend to be blurry at the edges. Additionally, when first gen devices are turned off, they produce a green glow that lasts a few minutes.
In spite of their shortcomings first, gen devices offer night vision capabilities at low costs. In fact, first, gen devices are the most common.
Night Vision Generation 2
Second generations function almost in the same manner as the first generation. However, second-generation devices come equipped with a microchannel plate or MCP. The latter is an electron amplifier consisting of many short parallel tubes. Thanks to this amplifier second generation devices can amplify light better than first gens. Therefore, second generations devices are clearer and more expensive.
Night Vision Generation 3
The addition of a chemical compound known as gallium arsenide to the photocathode makes third generation devices clearer and brighter. The photocathode in third gen devices is made of gallium arsenide, which makes images appear brighter and clearer. The advancements do not end there though, as the Micro-channel plate features an ion barrier film to enhance its lifespan. The result is a device that can amplify ambient light up to 50,000 times.
Night Vision Generation 4
It is said that generation four night vision technology is the most advanced. However, this might not be the truth. You see, fourth generation equipment features a filmless MCP. This resulted in improved clarity and brightness but reduced the lifespan of the image intensifier tubes. Today, many manufacturers opt to make night vision devices with a thin film. Thus, fourth-gen is sometimes referred to as generation 3+. The gen 3+ guarantees clarity and brightness while improving the tube’s lifespan.
How Does Night Vision Work ?
The question how does night vision work is one I am sure you have pondered on. To understand the secrets of night vision technology, it is important first to note that not all light is visible. I know it sounds crazy when say it out loud. But the human eye is only able to see specific types of lights. And unfortunately, ultraviolet and infrared lights are not visible to the naked human eye.
Night vision technology works in two different ways. The first is by use of image intensifier tubes, and the other is by use of thermal imaging.
To understand how night vision technology works it is important first to understand how light works.
Scientifically speaking, the amount of energy in a wavelength depends on how long it is. Shorter wavelengths have higher energy than longer. In this regard, violet has the highest amount of energy and red has the least. This applies to the light that is visible to the naked eye. Infrared light is not visible to the naked eye.
This type of light can be classified into near, mid and thermal infrared. Of the three thermal infrared occupies the larges spectrum of light and measures between 3 to 30 microns. The other two categories measure between 0.7 to 1.3 microns and 1.3 to 3 microns respectively.
Even in the darkest of nights, there is still light, which is not visible to users. Night vision goggles and binoculars use photo enhancers to amplify this light. By amplifying the invisible light, it becomes possible to see at night. These types of devices use image intensifier tubes to enable you to see at night. In theory night vision devices function this way;
Night vision devices have different components designed to enhance light. The first component is the photocathode. Light photons, which are small particles that make up light, enter a device through the objective lens and hit the photocathode. The latter converts the photons into electrons, which are small particles that carry electricity around a circuit. A photomultiplier then amplifies the electrons to make many more electrons. The electrons hit a phosphor screen, similar to the one found in old television sets. As the electrons hit this screen, they create flashes of light making it possible for you to see.
From your basic school science, you know that thermal has something to do with heat. That being said, everything on this earth emits heat in the form of infrared light. This light is; however, invisible to humans. Thermal imaging entails the detection of the infrared heat being emitted by objects in the field of view. Using small measurement devices called microbolometers thermal imaging tools detect animal movement by measuring the amount of heat being emitted. Thermal imaging technology is best suited in near total dark conditions.
Night vision devices are identifiable with their characteristic green glow. However, the electronic information transmitted through them is usually colorless. So where does the green glow come from? The phosphor screen that the electrons are transmitted to is intentionally designed to display things in color green, and for good reasons. You see our eyes are more sensitive to green light and can tolerate it for longer periods of time compared to colors white and black. In this regard, thanks to the green glow it is possible to use night vision technology for long hours without hurting your eyes.