What is the principle of anti-peeping film?

Privacy screens work in a similar way to blinds.

Venetian blinds block the outside view while letting in light through the concave and convex surfaces of the blades and the rotation of the blades. The privacy screen reduces the structure of the Venetian blinds by tens of thousands times, and controls the viewing angle of the screen through a parallel arranged grating structure. The spacing of the gratings is generally between 0.02-0.1mm.

When light is incident vertically on the privacy film, it can pass through unimpeded; as the angle of incidence of light increases, the light is gradually blocked by the shutter structure, and the amount of light passing through decreases accordingly.

Therefore, only the user facing the screen can receive enough light to see the screen clearly. Bystanders who are at a certain angle to the screen receive weaker light and it appears to be pitch black.

Source: Institute of Physics, Chinese Academy of Sciences

by Lychee Jelly

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