Generations of Night Vision.
- Gen 0 Night Vision
- Gen 1 Night Vision
- Gen 2 Night Vision
- Gen 3 Night Vision
- Gen 4 Night Vision
A night vision device is an optoelectronic device that enables images to be produced in levels of light approaching complete darkness. The image may be a conversion of visible light of both visible light and near-infrared while by convention detection of thermal infrared is denoted thermal imaging.
Night vision devices are mostly used by the military and law enforcement agencies but are available to civilian users as well.
Night Vision Devices feature an image intensifier tube, an objective lens, a power supply, and an eyepiece. They gather existing ambient light through the front lens.
This light which is made of photons gets into the photocathode tube changing the photons to electrons. The electrons then pass through a vacuum where they strike a microchannel plate which amplifies them before they hit a phosphor screen which changes them back into visible light (Photons) seen through the eyepiece.
Generations of Night Vision Explained
Generation 0
This is the original night-vision generation and was used during World War II .
Night Vision devices in this generation use active infrared.
So how does it work? an IR Illuminator is attached to the Night vision device to project infrared light beams, the beam reflects off objects to the NVD. Anodes and cathodes are also used for electrons acceleration ( this is disadvantageous since there is image distortion and tube destruction)
Gen 1 Night Vision
Generation 1 technology dates back to the early 1960s and depends on ambient light rather than using an infrared light source. It is affordable and hence great for those who need to stay within a budget range.
There is a great selection of Gen 1 products for you to choose from. It gets you some nighttime capability. It is however quite bulky and needs moonlight to work properly.
It is fine to use for many applications such as boating, observing wildlife, or providing security for homes but has some limitations such as:
- The maximum useful range is about 75 yards depending on the night.
- Lower-resolution images that are not as bright and have more static/noise
- The field of view is smaller because of the grotesque image on the outer one-third of the field of view
- Battery life is shorter
- Lacks the capability to operate passively as it depends on built-in IR illuminators that are always on making the user very visible to anyone using another night vision device
- Gen 1 monoculars lack the versatility that higher generations do. For instance, adapting to rifle scopes, weapon mounting capability, and spotting scopes.
- Life expectancy is shorter. Gen 1: about 1500 hours, Gen 2: about 5000 hours, and Gen 3 more than 10,000 hours.
- More susceptible to image distortion brought about by excessive light.
Gen 2 Night Vision
Gen 2 is a huge step from 1st generation equipment with regards to both quality and life expectancy. It was developed in the 1970s featuring an enhanced image-intensifier tube using a microchannel plate with an S-25 photocathode and leading to an image that is much brighter, especially around the edges of the lens.
This resulted in increased illumination in low ambient light conditions like moonless nights. It has the addition of a micro-channel plate that works as an electron amplifier and is placed directly behind the photocathode. The microchannel plate consists of millions of short parallel glass tubes.
When the electrons pass through these short tubes, thousands more electrons are released. This process lets the Gen 2 units amplify the light many more times offering an image that is brighter and sharper.
It is primarily used by law enforcement or for professional applications. Examples include AN/PVS-3 Miniaturized, AN/PVS-4, AN/PVS-5 and SUPERGEN.
Major improvements:
- Much longer useful range, in the 200-yard area based on the model
- Better resolution, cleaner and brighter images
- Capability to work passively without the necessity of IR illumination
- Battery life is longer
- Full-field of view with no grotesque image on the outer one-third of the viewing area
- Monoculars have increased durability and adaptability thus greater versatility
- Lower chances of being affected by blooming or image distortion caused by light
- 3 times longer life expectancy and better reliability
Gen 3 Night Vision
Third-generation night-vision systems date in the late 1980s, and maintain the MCP from Gen 2 but use a photocathode made with gallium arsenide which further enhances image resolution.
Additionally, the MCP is coated with an ion barrier film to increase the life of the tube. The ion barrier however causes fewer electrons to pass through, decreasing the improvement expected from the gallium-arsenide photocathode. Power usage is higher than in Gen 2 tubes. It offers brilliant performance and state-of-the-art capability.
These units perform the best under low light conditions without the help of IR. Many models provide the user the option of having an automated or manual gain tube. Gen 3 Night Vision is generally reserved for the military, law enforcement, and those seeking the best equipment on the market. Examples include AN/PVS-7, AN/NVS-7, AN/PVS-10, AN/PVS-14, AN/PVNS-14, AN/PSQ-20, CNVS-4949, and PN-21K.
Advantages
- Best low-light performance
- Operates in all light conditions due to the autogated Gen 3 image tubes that also reduce image distortion significantly.
- Greater versatility because of better performance when using with magnification lenses, scopes, camera adapters, and other night vision accessories
- Greater ability for an operation that is entirely passive without the use of IR illumination
- The longest life expectancy of over 10,000 hours
- Best reliability and durability
Gen 4 (Gen III OMNI IV-VII)
These devices developed in the 2000s and differ from the standard Gen 3 in one or both of two paramount ways:
- The photocathode is regulated by an automatic gated power supply system enabling the NVD to adapt to changing light conditions.
- A removed or greatly thinned ion barrier reduces the number of electrons that are normally rejected by the standard GEN 3 MCP thus resulting in less image loss and the ability to work with a luminous sensitivity. The disadvantage to a thin or removed ion barrier is the overall reduction in tube life. This is however largely negated by the low number of image-intensifier tubes that reach 15 000hof operations before replacement.
This type of system is classified as Generation 4 by the consumer market but the United States military describes these systems as Generation 3 autogated tubes (GEN-III OMNI -VIII).
Furthermore, as autogating power supplies can now be added to any previous generation of night vision devices, autogating capability doesn’t classify the devices as GEN-III OMNI-VII automatically. Any post-nominals coming after a generation type don’t change the generation type of the device but rather show enhancement over the original specification’s requirements.
Examples include AN/PVS-22, NVS-22, Ground Panoramic Night Vision Google (GPNVG-18), and Binocular Night Vision Device (BNVD).
White Phosphor Technology
White Phosphor Technology image tubes are now available in all generations. They have black and white images rather than traditional green and black. These images can appear more natural and offer better contrast in some situations.
White Phosphor has become more widely adopted by the military and law enforcement. It is solid quality night technology that appears to be here to stay.
Read more on Generations of Night Vision below