A Night Vision Device can be a 1 st , 2 nd , 3 rd generation unit. What this stands for, is what type of light intensifier tube is used for that particular device the light intensifier tube is the heart and soul of a night vision device.
The 1st generation is currently the most popular type of night vision in the world. Utilizing the basic principles described earlier, a 1st generation will amplify the existing light several thousand times letting you clearly see in the dark. These units provide a bright and sharp image at a low cost, which is perfect, whether you are boating, observing wildlife, or providing security for your home. You may notice the following when you are looking through a 1st generation unit .
A slight high-pitched whine when the unit is on.
The image you see may be slightly blurry around the edges.
When you turn a 1st gen off it may glow green for some time.
These are inherent characteristics of a 1st gen and are normal
The 2nd generation is primarily used by law enforcement or for professional applications. This is because the cost of a 2nd gen unit is approximately $500.00 to $1000.00 more then a 1st gen. The main difference between a 1st and a 2ndgeneration unit is the addition of a micro-channel plate, commonly referred to as a MCP. The MCP works as an electron amplifier and is placed directly behind the photocathode. The MCP consists of millions of short parallel glass tubes. When the electrons pass through these short tubes, thousands more electrons are released. This extra process allows 2nd generation units to amplify the light many more times then 1st generation giving you a brighter and sharper image.
The 3rd generation is operating with special chemicals, gallium arsenide to the photocathode. The brighter and sharper image is the major characteristics of a 3 rd generation. AnGE ion barrier film was also added to increase tube life. Gen. 3 provides the user with excellent light performance.
The Gen 3 technology improves night operational effectiveness for military users of night vision goggles and other night vision devices. The filmless MCP provides a higher signal-to-noise ratio than Gen 3, resulting in better image quality (less scintillation) under low-light conditions. The gated power supply further improves image resolution under high light conditions, and the reduced halo minimizes interference from bright light sources. These improvements also substantially increase the detection range of the systems.
What are the definitions of common night vision terms?
GAIN - The number of times a night vision device amplifies light input . Usually measured as tube or system gain, it commonly has values in the tens of thousands. US military image tubes typically operate between 12,000 and 65,000.
LINE PAIRS - a.k.a. line pairs per millimeter (lp/mm). This is a measurement of resolution. The more line pairs, the better the resolution. The best tubes are currently at 64+ line pairs. Generation 3 units will typically have 55 to 64 line pairs and are a factor to consider in price.
PHOTOSENSITIVITY - a.k.a. photocathode sensitivity. It is the ability of the photocathode to produce an electrical response when subjected to light waves (photons). The higher the value, the better the ability to produce a visible image under darker conditions.
RESOLUTION - The ability of an image intensifier or night vision system to distinguish between objects closer together, measure in line pairs per millimeter (lp/mm). There is a difference between system resolution and image intensifier resolution. System resolution can be affected by altering the objective or eyepiece optics, or by adding magnification lenses. Image intensifier resolution remains constant. System resolution is very important in determining the quality of a system.
SIGNAL-TO-NOISE RATIO - The low light resolution of the image tube. The higher the signal-to-noise ratio, the better the ability of the tube to display objects with good contrast under low light conditions. It is the single best indicator of an image intensifier's performance.
What are tube blemishes and small black dots
Tube blemishes are common in ALL image intensifier tubes. Image tubes are NEVER flawless, and every tube will have blemishes to some degree. The fewer and smaller the blemishes, the better the quality and therefore the higher the price.
Its a very important to state that small black dots can be easily visible during date time observation or testing of the night vision device. Therefore in most of the cases.
How Far Can You See With A Night Vision Device?
There are many different variables that can affect the distance that you can see with a Night Vision Device. First, what are you trying to see?
1) Are you looking for a boat on the water or are you looking for a rabbit in the woods?
The larger the object is the better it is to see.
2) Secondly, are you trying to see details (what we call recognition range) or are you just trying to see if something is there?
3) The more ambient light you have ( starlight, moonlight, and infrared light ) the better and further you will be able to see.
4) If you were looking across an open field with Generation 1 you could see a barn or a house 400-500 meters away.
5) If you were looking across an open field with Generation 2, 2+ you could see a barn or a house 500-700 meters away.
6) If you were looking across an open field with Generation 3 and there was no moon out you could see a barn or a house 700-1000 meters away.