Night Vision Optics

Presented By:

Alexis Carr, Matt Parunak, & Rekita Moody

Optical EngineeringDr. Kasra Daneshvar

July 12, 2002

Night Vision Optics

Abstract

In this study we will

attempt to disclose the

major aspects of night

vision technology and how

it has evolved over the

past forty years. Night

vision is simply having the

ability to see in the dark.

In many night vision

systems, the objective lens

collects small particles of

light called photons and

focuses them on an image

intensifier. Within the

image intensifier lies a

photocathode which

absorbs light energy and

converts it into electrons.

When the highly

intensified electron image

strikes the phosphor

screen, it causes the

screen to emit light which

can be seen with the

human eye. This process

allows one to see a

reflected image that

directly corresponds with

the outside image they are

viewing. Night vision

technology is considered

preeminent and is used

throughout the world in

various areas of life (“How

Night Vision Works”)

Image courtesy of Infrared, Inc.It is quite easy to see everything

during the day...

Image courtesy of Infrared, Inc.but at night, you can see

very little.

Image courtesy of Infrared, Inc.Night vision devices allow you to see again.

Introduction

Have you ever got up in the middle of the night and stumbled over an object in

the middle of the floor? Blinded by the darkness, you rush to the nearest light switch to

get an illuminated view of the area. Well, stumble no more; through advancement in

technology, special equipment has been produced to enable one to see through the

darkness. We call these highly esteemed devices, night vision optics. Originally

developed and used by the U.S. military to locate enemy targets at night; night vision

optics or devices, better referred to as NVDs, have revolutionized the history of human

vision.

Background

Night vision optics and devices have been around for over forty years. They were

first developed during World War II; as the United States, Great Britain, and Germany

aimed to produce basic night vision technology. This newfound technology would

enable these superpowers to maneuver their troops effectively through the night. Night

vision can trace its roots back to the development of the Research and Photometric

Section of the Corps of Engineering Research and Development Laboratory, which was

founded in February 1954. This organization is responsible for the progression of night

vision equipment for individual soldiers in the field. The basic objective began as “the

Conquest of Darkness so that the individual can observe, move, fight, and work at night

by using an image that can interpret without specialist training and to which he could

immediately respond”(“Night Vision”).

The following is a timeline, disclosing the evolution of night vision optics:

1951- Sniper scope1954- Metascope1955- First NIR Mapper1958- First IR Line Scanner1964- Starlight Scope1965- TVS-4 Night Observation Device1967- Pulse Gated I2-TVS-2 Crew Served Weapon Night Sight1969- First Laser Rangefinder (Ruby)1971- Handheld Thermal Viewer1971- FLIR Production 1971- PRS-7 Handheld Non-metallic Mine Detector1975- PVS-3 Miniscope1975- Night Vision thermal Model Publication1976- Common Module FLIR production1977- PVS- 5 night vision Goggles1981- VGS-2 Tank Thermal Sight1982- TAS-6 night Observation Device, Cong Range1984- AVS 6 ANVIS Goggles, Third Generation I21986- GVS- 5 Laser Rangefinder1987-PVS-7 Night Vision Goggles1988- AAS- 32 Airborne Laser Trader(“Night Vision”)

Understanding Night Vision

To fully comprehend night vision, it is imperative that one understands something

about light. The sum of energy in a light wave is related to its wavelength; the shorter the

wavelength the higher energy level they encompass. Of visible light, violet has the most

energy, and red has the least amount of energy. Next to the visible light spectrum lies the

infrared spectrum which is composed of light, that is invisible to the naked eye.

Infrared light is a small part of the light spectrum.

Infrared light can be separated into three categories:

Near- infrared (near- IR) - Closet to visible light, near-IR has wavelengths that range from 0.7 to 1.3 microns.

Mid –Infrared (mid- IR) - Mid - IR has wavelengths ranging from 1.3 to 3 microns.

Thermal – Infrared (thermal- IR)-Occupying the largest part of the infrared spectrum, thermal-IR has wavelengths ranging from 3 microns to over 30 microns.

Generations

There have been many adjustments and improvements made to night vision

devices. These advancements in night vision devices are categorized by generation.

Each major change in night vision technology institutes a new generation. The

generations are numbered from zero to three and progress from the original active

infrared devices to the latest and greatest passive infrared devices with better resolution

and sensitivity.

Generation 0: The original night vision system was created by the United States

Army and used in World War II and the Korean War. The first night vision devices,

(NVDs), used active infrared. The problem with these devices was that the pattern was

easy to duplicate and was easily imitated by hostile nations, thus allowing enemy soldiers

to use the NVDs to see the beams projected by U.S. devices.

Generation 1: The next generation of NVDs moved away from active infrared,

and used passive infrared in its place. Also referred to as Starlight by the U.S. Army,

these NVDs use ambient light provided by the moon and stars to augment the normal

amounts of reflected infrared in the environment. Although these NVDs were much

better than the ones existing in generation zero, they used a weak image intensifier which

resulted in image distortion.

Generation 2: Major improvements in image- intensifier tubes offered improved

resolution and performance over generation one devices and were considerably more

reliable. The biggest gain in generation two was the ability to see in extremely low light

conditions, for instance moonless nights.

Generation 3: The latest and greatest night vision technology currently exists in

generation three. Although there are no major changes in the technology from generation

two, the generation three devices have even better resolution and sensitivity. These night

vision devices are considered state of the art. They are well protected and cannot be

exported from the United States without proper permission from the United States

Department of State. The recipient(s) must also provide details concerning themselves

and the purpose the devices will serve (Tyson, 1998-2002).

Conclusion

Photo courtesy of B.E. Meyers CompanyThis soldier is using DARK INVADER night-vision goggles.

Night vision devices and optics are used for many purposes. The military

continues to use them to locate enemy targets as well as for navigation and surveillance.

However, the usage of these devices has extended beyond the boundaries of the military.

Police and security often use night vision optics for surveillance and in solving cases.

Hunters and nature enthusiasts use the optics to maneuver through the woods at night.

Detectives and private investigators use night vision to watch people they are assigned to

track. Even some businesses have permanently-mounted cameras equipped with night

vision to monitor the surroundings. As people discover the unique ability of these high

performance devices, night vision optics will continue to modernize the way we see.

REFERENCES

“How Night Vision Works”. Retrieved June 25, 2002, from<http://www.night-

vision-gear.com>

“Night Vision”. Retrieved July 1, 2002, from www.nvl.army.mil/home.html

Tyson, Jeff. (1998-2002). Retrieved June 26, 2002, from

www.howstuffworks.com/nightvision.htm