Shadow Mask

What Does Shadow Mask Mean?

A shadow mask is a metal sheet with holes punctured in a regular pattern that is present inside a color monitor. It is a part of a cathode-ray tube (CRT) setup where the electron beam, after generation from an electron gun source, is directed toward the screen to create images. The beam is focused by making it pass through the shadow mask.


Techopedia Explains Shadow Mask

A shadow mask directs the electron beam by absorbing the electrons that are going in the wrong direction so that the beam only hits the desired points and the resulting picture is not blurred. CRTs have three electron guns — red, green and blue — present for color display. These guns direct their beams to the shadow mask which allows them to pass, if the beams fall on a hole. Since the guns are physically discrete, the beams reach the shadow masks from slightly different levels. It is the task of a shadow mask to direct each beam on its respective dot on the screen and form an intelligible picture on the screen.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.