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Season Four Research Files
Episode Thirteen
7:00pm - 8:00pm
Night Vision scopes and binoculars are electro-optical devices that intensify (or amplify) existing light instead of relying on a light source of their own. The devices are sensitive to a broad spectrum of light, from visible through infrared. The user does not look "through" a night vision product, but instead sees the amplified electronic image on a phosphor screen.
Light enters the scope through an objective lens and strikes a photo cathode that has a high-energy charge. This charge accelerates across a vacuum inside the intensifier and strikes a phosphor screen (like a TV screen) where the image is focused. The eyepiece magnifies the image. The phosphor screen is purposefully colored green because the human eye can differentiate more shades of green than other phosphor colors.
Many night vision devices might be damaged when used during the daytime or whenever there is sufficient light to see the object. And strong direct light, such as projectors, car headlamps and strong flashlights may be harmful when glared into the unit, creating a halo effect on the image. Other night vision scopes incorporate technology that readjusts to a shining light. Yet the scopes still require some time to make the adjustment.
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