Night vision devices gather existing ambient light
(starlight, moonlight or infra-red light) through the front lens. This
light, which is made up of photons goes into a photocathode tube that
changes the photons to electrons. The electrons are then amplified to a
much greater number through an electrical and chemical process. The
electrons are then hurled against a phosphorus screen that changes the
amplified electrons back into visible light that you see through the
eyepiece. The image will now be a clear green-hued amplified
re-creation of the scene you were observing.
1. Front Lens
4. High Voltage Power Supply
5. Phosphorus Screen
3. Microchannel plate
FIRST, SECOND, THIRD AND FOURTH GENERATION
A Night Vision Device can be either a 1st, 2nd, 3rd
or 4th 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 an NVD.
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 gen unit
A slight high-pitched whine when the unit is on.
The image you see may be slightly blurry around the edges. This is known as Geometric Distortion.
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.
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
2nd generation 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.
3rd generation By adding a sensitive chemical, gallium arsenide to the photocathode a
brighter and sharper image was achieved over 2nd generation. An ion
barrier film was also added to increase tube life. Gen. 3 provides the
user with good to excellent low light performance.
4th Generation / Gated Filmless tubes:
generation / Gated Filmless technology represents the biggest
technological breakthrough in image intensification of the past 10
years. By removing the ion barrier film and "Gating" the system Gen 4
demonstrates substantial increases in target detection range and
resolution, particularly at extremely low light levels.
The use of filmless technology and auto-gated power supply in 4th generation image intensifiers result in:
Up to 100% improvement in photoresponse.
Superb performance in extremely low light level (better S/N and EBI)
At least triple high light level resolution (a minimum of 36 lp/mm compared to 12 lp/mm)
With significant improvement in contrast level and in performance
under all light conditions, 4th generation represents the top of the
line performance in the night vision market. Note: The term 4th
generation is used/accepted among Night Vision manufactures to describe
gated filmless tubes. However, this designation is widely debated and
is currently referred to as Filmless & Gated image intensifiers by
the US Military.
Gen 4 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
Relative direction ranges
Overcast Starlight Conditions (-1x10E-5 tc)
Vehicle Size Target, 30% Contrast
Gen 3 OMNI
I and II
Gen 3 OMNI
Gen 3 OMNI
Detection Range (m)
over Gen II
Gen IV technology is not currently available for export.
Starlight scopes need some light to amplify. This means that if you
were in complete darkness you could not see. Due to this we have a
built in infra-red illuminator (IRI) on all of our scopes. Basically
what an IRI does is throw out a beam of infra-red light that is near
invisible to the naked eye but your NVD can see it. This allows you to
use your scope even in total darkness. The IRI works like a flashlight
and the distance you can see with it will be limited. We do use the
most powerful eye-safe illuminator on the market. This allows our IRI
to extend out to 100 yards However, because of the power at a short
distance the IRI may cover only 40-60% of the viewing area.
HOW FAR CAN YOU SEE
There are many different variables that can effect the distance that
you can see with a Night Vision device. First, what are you trying to
see? Are you looking for another boat on the water or are you looking
for a rabbit in the woods? The larger the object the easier it is too
see. Plus, are you trying to see details (what we call recognition
range) or are you just trying to see if something is there or maybe you
will just see movement but won't be able to 100% determine who or what
it is. This is called detection range. Second. Another variable is
lighting conditions. The more ambient light you have (starlight,
moonlight, infrared light) the better and further you will be able to
see You can always see further on a night where the moon and stars are
out then if it is cloudy and overcast. We typically state that you can
tell the difference between a male and a female or a dog and a deer at
about 75 to 100 yards. However, if you were looking across an open
field and there was a half moon out you could see a barn or a house 500
Remember, that the purpose of an NVD is to see in the dark not necessarily a long ways like a binocular.
BLACK SPOTS ON THE SCREEN
you look through a night vision device you may notice black spots on
the screen. A NVD is similar to a television screen and attracts dust
and dirt. Typically these spots can be cleaned. However, this may also
be a spot in the tube itself. This is normal. Most tubes will have some
spots in them. These black spots will not affect the performance or
reliability of the night vision device.