Start with the basics:
All Night vision devices consist of two fundamental parts;
1) the core technology i.e. the image intensifier tube; and
2) the housing kit i.e. the housing and optics.
1) Image intensifier tubes are like diamonds - no two are the same. The long, complicated and multi-tiered manufacturing process leaves room for film defects, cosmetic blemishes, spots, and other potential problems. As a result, each image tube comes out of the manufacturing process completely different from any other.
Because the manufacturing process is long, complicated, and expensive for obvious reasons, there are only a handful of manufacturers willing to take on creating an image intensifier tube that is rugged and durable enough to use for the military and law enforcement applications. The U.S. manufacturers are ITT Exelis, and Litton/Northrup-Grumman - recently acquired by L-3. European manufacturers, such as Photonis, predominately create Generation 2/+ image tubes, which are not comparable to the quality, utility and overall performance of U.S. manufactured Generation 3 image tubes. There are also image tubes manufactured by other companies around the world, but the end product is not rugged or durable enough to withstand U.S. military and law enforcement abuse, so the application for those tubes remains industrial or in production processes. Although, those tubes do find their way into low cost, cheap ground based night vision applications and get sold to a commercial market of apathetic unsuspecting buyers. They also,unfortunately, find their way into law enforcement hands when procurement and contract officers look for the lowest cost devices to outfit a particular agency.
The technological developments of night vision technology (i.e. image intensifier tube technology) has traditionally been measured by U.S. Omnibus contract requests for improvement. These are also known as "Generations". U.S. Omnibus contracts are very large acquisitions by the military of night vision equipment. We are presently at Omnibus VII and awaiting results for Omnibus VIII.
To date, there have been four generations of l² (Image Intensification) devices, identified as Gen 0, Gen 1, Gen 2, and Gen 3. Developmental laboratory work is on-going. However, no definition for Gen 4 by the U.S. Military presently exists. See below.
Generation 0 The first night vision aids (also called Generation Zero or Gen 0) were sniper scopes that came into use during World War II and the Korean conflict. These were not true image intensifiers, but rather image converters, which required a source of invisible infrared (IR) light mounted on or near the device to illuminate the target area.
Generation 1 The "starlight scopes" developed during the early 1960's for use in Vietnam were the first Generation (Gen 1) of image intensifier devices. In Gen 1 night vision units, three image intensifiers were connected in a series, making the units longer and heavier than future night vision units would be. Gen 1 equipment produced an image that was clear in the center of the field of view but suffered from large optical distortion around the periphery. Gen 1 equipment was also subject to "blooming". Most low-cost imported night vision units use Gen 1 technology, though often under the guise of a higher "generation".
Generation 2 The development of the microchannel plate, or MCP, in the late 1960s brought on the second generation (Gen 2) in l² night vision. The MCP accelerated and multiplied electrons which provided the gain previously supplied by coupling three image intensifiers together (Gen 1). The introduction of the MCP significantly reduced size and weight for image intensifier tubes, enabling design of smaller night vision goggles and hand-held devices. The MCP also provided much more robust operation when bright lights entered the field of view. The Gen 2 tubes used the same tri-alkali photocathode as the Gen 1 devices. This generation was implemented to reflect the change in how the light was amplified (MCP versus three-stage coupling). 
Generation 3 Third-generation (Gen 3) image intensifiers were developed in the mid-1970s and became available during the early 1980s. Gen 3 introduced two major technological improvements: the gallium arsenide (GaAs) photocathode and the ion barrier coating to the microchannel plate. The GaAs photocathode increases the tube's sensitivity to light from the near-infrared range of the spectrum, enables it to function at greater detection distances, and improves system performance under low-light conditions. Application of a metal-oxide ion barrier to the MCP increases the life of the image tube. The operational life of Gen 3 tubes is in excess of 10,000 hours, compared to that of Gen 2 tubes which is about 2,000 to 4,000 hours. This generation was implemented to reflect the change in the photocathode (tri-alkali replaced with GaAs).
Myth vs. Fact: Generation 4 Some say that generation (Gen) 4 is the most advanced night vision you can buy. This is not the case. As mentioned above, historically, the U.S. Army has defined each Generation of night vision. In the late 90's the Army did define Gen 4 as the removal of the ion barrier film creating a "filmless" tube. This new advancement was to reduce halos while increasing sensitivity, signal-to-noise ratio (SNR) and resolution, for overall improved performance. While performance was improved, the lack of an ion barrier in Gen 4 tubes led to high failure rates, ultimately leading the U.S. Army to recant the existence of Gen 4 definition. Recognizing the high failure rates of Gen 4 tubes, ITT Exelis chose to improve upon the existing Gen 3 technology and create a "thin-filmed" tube. By keeping the protective ion barrier, but greatly reducing its thickness, Exelis was able to maintain the reliability of Gen 3 while at the same time delivering on the Army's performance requirements intended for Gen 4. This innovation resulted in the production of the Gen 3 thin-filmed tube, which is now the highest performing Gen 3 tube available.
Generation 3 PINNACLE® The Gen 3 thin-filmed tube with a standard power supply was the end result of the Generation 4 developments. However, the need for a system that was able to withstand sudden exposure to light was still in demand. Subsequently, ITT Exelis added auto-gated power to the thin-filmed tubes and the PINNACLE® tube was born. PINNACLE® night vision technology represents the apex in image intensifier tube development. The super thin-film (10,000 times thinner than a human hair) minimizes blooming caused by bright light exposure, while the auto-gating diminishes power to the system thereby decreasing the amount of amplified light allowed into the unit. Perfect for tactical operations allowing users to complete their mission objectives without the risk of being blinded by sudden exposure to bright light, as is the case with traditional night vision equipment.
In summary, ITT Exelis, the U.S. military's #1 supplier of night vision equipment for both ground and air applications, does not manufacture a Generation 4 night vision tube. Litton - Northrup/Grumman does, in fact, manufacture a filmless auto-gated image tube, however, the military would not buy it for the reasons stated above. Hence, the Generation 4 technology exists, but the definition was never qualified by the military. So, the question is,... "Do you want to purchase a Gen 4 night vision device that the military doesn't want or recognize as fit for service?
2) Housings and Optics: Housing kits can be likened to a wrist watch; many are cheap Russian imitations of original U.S. designed and manufactured night vision housings. U.S. manufactured housing kits are typically better made and more durable. The housing for the NEPVS-14, utilizes the same housing and optics as it's sister piece being currently used in the military. The optics can also be a huge factor in night vision performance. Precisoned lenses and optics can turn a Gen 3 system into an even higher performing system. Many people don't realize that, and rather focus on the tube specifications.
All the different names of night vision systems (Knock-offs): Knock-offs use similar nomenclature to battle proven U.S. Military specification systems but use inferior optics and substandard poorly machined materials that do not stand up to the rigors of law enforcement and/or military requirements. Knock-offs are made only for the commercial markets, but use similar military nomenclatures to confuse the consumer. Don't accept substitutes that use similar nomenclatures such as AN/PBS-14 or NB-14, etc., etc., etc... the list goes on.
Putting it all together, you have a night vision system that might look good on paper - but when it reaches the front line end user - beware!
Saving a few hundred dollars per unit might be the difference between completing a mission or not completing it, or worse, it could cost a life.
What to look for:
Demand only U.S. name brand, factory warranted systems direct from the primary U.S. manufacturer and/or its authorized dealers. Name brand systems include ITT Exelis Night Enforcer® NEPVS-14, and Morovision Night Vision systems including the MV-14P PINNACLE® Monocular and PVS-7 Goggle Gen 3 PINNACLE®. All of these U.S. Military battle proven systems utilize factory new, Generation 3, 64 lp/mm resolution (Typical) SELECT Exelis image tubes, full Mil-Spec nitrogen purged housings and optics and include a comprehensive manufacturer's warranty. Look for the manufacturer's I.D. label with serial # located on the side of the system housing.
Morovision Night Vision is the Authorized U.S. Law Enforcement Distributor and a Commercial Tube Distributor of ITT Exelis.
ITT Exelis (www.exelisinc.com) is the world's leading developer, producer and supplier of Generation (Gen) 3 image intensifier technology for U.S. and allied military forces as well as the homeland security market. Exelis has served the U.S. military with premier night vision solutions for nearly 50 years and delivered its one millionth Gen 3 image tube in 2007.
Exelis systems such as the popular NEPVS-14 monocular have successfully provided the U.S. Military with significant advantages in night time operations and continue to give domestic law enforcement officers, investigators, and homeland security professionals those same advantages.
See also: ITT Exelis Image Intensifier Tubes
See also: ITT Exelis PINNACLE® Image Intensifier Tubes
See also: How Night Vision Works
Please Note: This webpage is the sole and exclusive content of Morovision Night Vision, Inc. and may not be republished or rewritten without the prior written consent of Morovision Night Vision, Inc.
See LAW + ORDER Magazine Article: Selecting Image Intensifiers, Thermal Imagers & Night Sights by Charlie Cutshaw, January 2008
