How does Night Vision Goggles work?

How does Night Vision Goggles work?

Last week, I was watching an English movie, in which few soldiers switched off the lights of a room and started firing in the dark after wearing some special kind of goggles enabling them to view even in the dark.

Now after a week, I got to read about those special goggles called as ‘NIGHT VISION GOGGLES’. Well these so called night vision goggles are one of the applications of Semiconductor Physics.

So in this post, I would like to share with you what i have read about these Goggles.

Well, the components present in a night vision goggles can be divided into 3 parts namely,

Night Vision Goggle
  1. Photocathode
  2. Photomultipliers
  3. Phosphor Screen

First of all when the light is switched off, the dim light enters the lens of the Goggles. As everyone may know that light is essentially composed of photons, so we may say that the photons enters the lens and then strikes the first component of this device called photocathode. These photo cathodes are basically light sensitive semiconductor surface, which converts the photons into electrons. In simple words, it converts the light energy to electrical energy.

Now the electrons generated in the first stage enters the second component of the device and are passed through photomultipliers. As the name suggests, the job of the photomultiplier is to multiply the number of electrons entering its surface. So the number of electrons increases after coming out of the photomultiplier and is passed on to the next component.

Now in the third stage, the electrons strike the phosphor screen which give rise to tiny flashes of light.  These light flashes appear in the screen giving an idea of the location of a particular object in dark rooms.

If you have any more information on this topic, then do comment below and let all of us know.  Also do not forget to share if you find it informative.

Reference: Economic Times Magazine, Dated: Aug-12-2012

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