Night Optics Usa, Inc - Your exclusive source for premier quality Night Vision equipment

Night Vision: Binoculars, Goggles, Scopes, Sights; Day/Night Systems; Night Vision Accessories; Daytime Optics

Phones: 1-800-30-NIGHT, +1-714-899-4475; Fax: 714-899-4485; E-mail: sales@nightoptics.com

Professional Quality Night Vision Systems for Commercial, Law Enforcement and Military Applications

NIGHT OPTICS USA, Inc.
5122 Bolsa Ave.
Suite 101,
Huntington Beach,
CA 92649
1-800-30-NIGHT,
714-899-4475
Fax 714-899-4485
sales@nightoptics.com

Authorized Dealers

How Night Vision Works

[1] Front Lens; [2] Photocathode; [3] Microchannel Plate; [4] High Voltage Power Supply; [5] Phosphor Screen; [6] Eyepiece; [7] Image Intensifier

The objective lens (1) of a night vision device collects light that can’t be seen with the naked eye and focuses it on the image intensifier (7). Inside the image intensifier a photocathode (2) absorbs this light energy and converts it to electrons. These electrons are then drawn toward a phosphor screen (5). In 2nd and 3rd generation intensifiers the electrons first pass through a microchannel plate (3) that further multiplies them thousands of times. When this highly intensified electron image strikes the phosphor screen (5), it causes the screen to emit visible light. Since the phosphor screen emits this light in exactly the same pattern and contrast as collected by the objective lens, the bright nighttime image seen through the eyepiece corresponds precisely to the observed scene.

Generation 1

Typically uses an S-20 photocathode (with photosensitivity of 180-200 µA/lm) and electron acceleration to achieve gain. Gen 1 devices perform best when ambient light (moonlight or starlight) or sufficient IR illumination is available. Geometric distortion (fish-eye effect) is inherent in all Gen 1 devices. Life span of a Gen 1 tube (image intensifier) is approximately 1500 hours of continuous operation.

Generations 2, 2+ and Super Gen

Usually uses an S-25 (extended red) photocathode (with minimum photosensitivity of 240 µA/lm) plus a microchannel plate to achieve gain. Gen 2 devices provide than better-satisfactory performance at low light levels and exhibit very low distortion. Life span of a Gen 2 tube is approximately 2500-3000 hours of continuous operation. Newly developed European “Super-Gen” tubes which achieve performance levels of early versions Gen 3 Image Intensifiers can be a valuable alternative to standard Gen 2+ tubes.

Generation 3

The most advanced level of night vision technology, Gen 3 uses gallium-arsenide for the photocathode (with photosensitivity of more than 800 µA/lm in the 450 to 950 nanometer - near infrared - region of the spectrum) and a microchannel plate for gain. The microchannel plate is also coated with an ion barrier film to prolong tube life. Gen 3 provides very good-to-excellent performance in extreme low-light levels. Recent Mil Spec quality tubes have no perceptible distortion. Life span of a Gen 3 tube is 10,000+ hours of continuous operation.

At the present US Armed forces are issued NVDs with expanded sensitivities in the deep IR range. On a limited basis these technologies are beginning to become available commercially for the US and its allies.

NOTE: Manufacturer data sheets guaranteeing a minimum resolution of 64lp/mm are included with Night Optics USA night vision devices configured with Gen 3 US SELECT "A" image intensifiers.

Evaluation

Users have difficult choices to make among Generations of technology (Gen 1+, Gen 2 or Gen 3) or among competing options within a given generation. Evaluation of night vision equipment usually revolves around four major areas of consideration:

Performance:

Clarity of a night vision device image under varying light conditions. Performance is a product of image intensifier Photosensitivity, Signal-to-Noise Ratio, System Gain, and Resolution.

Human Factors:

Issues such as ease of operation, size, weight, technique of employment, and use of necessary or optional accessories are critical.

Suitability:

Selecting the right night vision device for the right application. Important considerations are Versatility, Adaptability, Field of View, Magnification, Weather Resistance and Fragility/Ruggedness of the system.

Overall Cost of Ownership:

Users should consider such issues as optional accessories, expected tube life, warranty coverage, ease and likelihood of repair, susceptibility to bright light exposure, and type and availability of batteries.

Contact Night Optics USA for assistance in evaluating night vision equipment.

Resolution

The ability of an image intensifier or night vision system to distinguish between objects close together. Image intensifier resolution is measured in line pairs per millimeter (lp/mm). While high quality Gen 3 Image Intensifiers can achieve tube resolution in the 64 to 72 lp/mm range, overall system performance can be dramatically degraded by use of poor quality optics. Night Optics USA integrates the highest quality optics in its products to insure optimum performance.

IR Illumination

Regardless of generation all image intensifiers require some light to function. In situations where ambient light is insufficient Infrared (IR) Illuminators facilitate night operations by providing an independent source of light. Since IR illuminators operate in near infrared range of 700 to 900 nanometers (nm) they are invisible to the naked eye.

Signal-to-Noise Ratio (SNR)

The ratio of light signal to perceived noise reaching the eye. An image tube’s SNR determines its resolution capability. Therefore, the higher the SNR, the better a tube is able to resolve objects with good contrast under low-light conditions. The best single indicator of an image intensifier’s performance.

Black Spots

Cosmetic blemishes in the image intensifier which do not affect the performance or reliability of a night vision device. Some number of varying sizes is inherent in the manufacturing process.