NVG NOMENCLATURE, CHARACTERISTICS, LIMITATIONS, AND OPERATIONS Flashcards
Describe how light passes through the ANVIS.
OPMPFE
Other People’s Money Pays For Everything
Objective Lens (inverts image, minus blue filter)
Photocathode (changes photons to electrons)
Microchannel Plate (multiplies electrons)
Phospher Screen (electrons to protons, creates the lighted image)
Fiber Optic Inverter (inverts the image)
Eyepiece Lens (allows the eye to see the image)
What is Automatic Brightness Protection (ABC)?
ABC automatically adjusts microchannel plate (MCP) voltage to maintain image brightness at preset levels by controlling the amount of electrons that exit the MCP. ABC is to protect the wearers vision, not to protect the goggles.
What is Bright Source Protection (BSP)?
Reduces the voltage to the photocathode when exposed to bright light sources. This protects the goggles from damage and enhances its life (however, it lowers resolution). Exposure to bright light sources could result in damage to the photocathode, MCP, or the operator’s eye.
What is an operational defect?
Defects that relate to the reliability of the image intensifier and are an indication of instability. An operational defect is an immediate cause for rejection.
What are the operational defects?
FESE
Flashing, Flickering, or Intermittent Operation
Edge Glow
Shading
Emission Point
Describe Flashing, Flickering or Intermittent Operation.
Light appears to flicker or flash. Can be in either one or both monoculars.
Describe Edge Glow.
A bright area in the outer portion of the viewing area (could be caused by a series of emission points). Check by covering the light entering from the objective lens. If it remains, it is edge glow.
Describe Shading.
You will not see a fully circular image, regardless of the adjustment. Begins at the edge and works inward. There will be a high contract area with a distinct line of demarcation.
Describe an 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 OBJ lens.
What is a cosmetic blemish?
A manufacturing imperfection / maintenance imperfection that does not affect image intensifier reliability. Not normally a cause for rejection unless they interfere with ability to perform the mission.
What are the cosmetic blemishes?
IF I C BOB
Image Distortion
Fixed Pattern Noise
Image Disparity
Chicken Wire
Bright Spots
Output Brightness Variation
Black Spots
Describe Image Distortion.
Evidenced by vertical objects (poles / trees) appearing to bend when you move your head vertically or horizontally. Ground surfaces may appear to swell or sink as well.
Explain Fixed Pattern Noise.
AKA Honeycomb
Faint hexagonal pattern throughout the viewing area that most often occurs at highlight levels.
Explain Image Disparity.
Difference in brightness between the two image intensifier assemblies within the same binocular.
Explain Chicken Wire.
An irregular pattern of dark thin lines in the field of view either throughout the image or in parts of the image. Under worst conditions, these lines will form hexagonal shaped lines (think of it as the beginning of honeycomb)