IMAGE INTENSIFIER

An electro-optical device that detects and amplifies ambient light to produce a visual image. It consists of a photocathode, microchannel plate, phosphor screen optics, and integral power supply.

PHOTOCATHODE

The input optic of an image intensifier that absorbs light energy and in turn Releases electrical energy in the form of an electron image.

MICROCHANNEL PLATE

A current-multiplying optical disk that intensifies the electron image produced by the photo-cathode.

GAIN

This is the number of times a night vision device amplifies light input.

OBJECTIVE LENS

This consists of an objective lens cell and an objective focus ring. It attaches to the front of the night vision devices and adjusts for variations in distance to the viewed area or object.

BLACK SPOTS

These are cosmetic blemishes in the image intensifier of the night vision device or dirt or debris between the lenses. Black spots are acceptable as long as they do not interfere with image viewing.

SHADING

The viewed image should be a full circle. If shading is present, you will not see a fully circular image. Shading is indicative of a dying photocathode and is caused by a defective vacuum seal of the image intensifier. Shading is very dark and you cannot see an image through it.

CHICKEN WIRE

An irregular pattern of dark thin lines in the night vision device’s field-of-view either throughout the image area or in parts of the image area. Under the worst condition, these lines will form hexagonal or square-wave shaped lines.

EMISSION POINT

A steady or fluctuating pinpoint of bright light in the image area and does not go away when all light is blocked from the objective lens of the night vision device. The position of an emission point within the image area of the goggles does not move. An emission point should not be confused with a point light source in the distance.

SCINTILLATION

A faint, random, sparkling effect throughout the night vision device’s image area. Scintillation is a normal characteristic of the night vision image intensifier and should not be confused with emission points. Scintillation is more pronounced under low light conditions. Also called “video noise.”

FIXED-PATTERN NOISE

This is a cosmetic blemish in the image area characterized by a faint hexagonal (honeycomb) pattern throughout the viewing area that most often occurs at High light levels or when viewing very bright lights. Fixed-pattern noise is inherent in the structure of the fiber optics and can be seen in every image intensifier if the light level is high enough.

FLASHING

This is a defect in which the night vision device image appears to flicker. This occurs in the night vision image intensifier. If there is more than one flicker, check for loose wires, loose cap, or weak batteries.

INFINITY FOCUS

Adjustment of the night vision device’s objective lens so that a distant object, such as a star or the point light on a distant tower, forms the sharpest image.

INTERMITTENT OPERATION

This a defect in the image area of the night vision device.

IR SOURCE

This is an IR Light Emitting Diode (LED). When turned on, the IR Source provides additional illumination to enhance existing light conditions and aid performance of the night vision device.