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
2. Photocathode
5. Phosphorus Screen
3. Microchannel plate
6. Eyepiece
FIRST, SECOND, THIRD AND FOURTH GENERATION NIGHT VISION
ATN 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 any night vision device.
1st generation of ATN Night Vision 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
of ATN Night Vision 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 generationATN Night VisionBy 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 from ATN Corp:
4th 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.
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.
ATN
Gen 4 Night Vision 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.
ATN Gen IV Night Vision technology is not currently available for
export.
Night Vision Goggles and Scopes with XD-4 Image Intensifiers
The XD-4 is the top grade of the DEP Image Intensifiers.
With the introduction of the XD-4 technology a new European Standard for low
light imaging was born providing unprecedented performance in Night Vision
applications.
The XD-4 Image Intensifiers perform extremely well in all environmental
conditions. Its wide spectral sensitivity range ensures that a perfect
picture is obtained regardless of the user's environment (foliage, on
water, snow, desert, rocky and barren land) or light conditions (down to
heavily overcast starlight).
The XD-4 Image Intensifiers provide as well a superb image under very
dynamic light conditions.
The basis for the unique performance of the XD-4 is the
technology used by DEP. This has resulted in greatly improved performance
parameters that are crucial for good observation, such as the
Signal-to-Noise Ratio (SNR), the Modulation Transfer Function (MTF) and
Resolution under all circumstances. Add to this the very long lifetime
throughout its complete luminance dynamic range and you will be convinced of
its unique performance.
The performance parameters of the XD-4 Image Intensifier are listed in
the table below. Highlights of the XD-4 specification are the typical
SNR of 24, the resolution of 64 lp/mm and over and - very important -
the high MTF at low and intermediate spatial frequencies. The latter
gives the image its sharpness and contrast.
It goes without saying that the XD-4 tubes can be
supplied in every common mechanical construction including inverting and
non-inverting fibre-optic output, which also means that users have the
opportunity to upgrade the performance of existing Night Vision Equipment
via a drop-in XD-4 Image Intensifier.
Technical specifications of XD-4 technology image
intensifiers available in ATN Night Vision devices:
Resolution
Minimal
Typical
Maximal
UNIT
Limiting resolution
Type I
55
58
lp/mm
Type II
60
64
lp/mm
Modulation Transfer Function:
2.5 lp/mm
92
%
7.5 lp/mm
80
%
15 lp/mm
58
%
25 lp/mm
38
%
30 lp/mm
30
%
Signal to Noise
Minimal
Typical
Maximal
UNIT
Signal to noise (@108çlx)
20
24
Other Technical Data
Minimal
Typical
Maximal
UNIT
Phosphor: P20*
MTTF (to S/N=12)
15.000
hrs
Gain at 2.10-5 lx
30.000/p
50.000/p
cd/m2/lx
Max. Output Brightness
2
17
cd/m2/lx
E.B.I.
0.15
0.25
lx
Output uniformity at 2850K
2:01
3:01
Weight(18mm)
80
95
grams
Shock
500
g
Luminous sensitivity at 2850K
600
700
uA/lm
Radiant sensitivity at 800nm
50
60
mA/W
Radiant sensitivity at 850nm
40
50
mA/W
DEP Image Intensifiers with XR-5
Technology
As a result of sustained and continuing product
development, DEP is proud to introduce the latest, innovative XR5 Image
Intensifier with unprecedented performance for any environment and any
circumstance.
The XR5 Image Intensifier, successor to the well-known
and successful XD-4 Image Intensifier, reveals even more details of the
night and offers an eXtended Range (XR) capability thanks to its new
technology.
Furthermore, the XR5 Image
Intensifier enables the user to see even more during a full 24-hour
day/night operation. This is done by the use of a fully integrated
Auto-Gating unit, which controls the image not only during day-night-day
transitions but also during dynamic lighting conditions such as those
experienced, for example, in night operations in urban areas. In
practice, this means no blooming to hinder your mission but dependable
imagery throughout. In addition, the halo is the smallest on the market.
The XR5 Image Intensifier from DEP represents the new
European standard for Night Vision and is available in a variety of
inverting and non-inverting 18 mm formats.
The new XR5 is your best choice to maintain your combat effectiveness under
all circumstances.
Technical specifications of XR5 technology image intensifiers:
Resolution
Minimal
Typical
Maximal
UNIT
Limiting resolution
64
70
lp/mm
Modulation Transfer Function:
2.5 lp/mm
93
%
7.5 lp/mm
82
%
15 lp/mm
67
%
25 lp/mm
46
%
30 lp/mm
35
%
Signal to Noise
Minimal
Typical
Maximal
UNIT
Signal to noise (@108çlx)
25
28
Luminance dynamic range
Minimal
Typical
Maximal
UNIT
Auto-Gating and Automatic Brightness Control
1.0E-06
5.0E+04
lux
Other Technical Data
Minimal
Typical
Maximal
UNIT
Phosphor: P20*
Reliability
15.000
hrs
Gain at 2E-05 lux
30.000/p
50.000/p
cd/m2/lx
Max. Output Brightness
2
17
cd/m2
E.B.I.
0.25
ulx
Luminous sensitivity at 2850K
700
800
uA/lm
Radiant sensitivity at 800nm
65
78
mA/W
Radiant sensitivity at 850nm
50
65
mA/W
Input voltage
2
3.7
volt
Input current
35
mA
Output uniformity at 2850K
1.8:1
3:01
Weight (18mm)
80
95
g
Shock
500
g
NIGHT VISION INFRA-RED ILLUMINATORS
All 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 WITH NIGHT VISION SCOPE
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 yards away.
Remember, that the purpose of a Night Vision Device is to see in the dark not necessarily a
long ways like a binocular or spotting scope.
BLACK SPOTS ON THE SCREEN
As 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.
All 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. 
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 yards away.
Remember, that the purpose of a Night Vision Device is to see in the dark not necessarily a
long ways like a binocular or spotting scope. 
As 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.