US Patent 9444508 Magnetic privacy filter

A magnetic privacy filter is disclosed. The magnetic privacy filter is adapted to protect the screen of a mobile device and has an anti-peep function. The magnetic privacy filter includes a filtering element and several ferromagnetic elements embedded in the filtering element. Accordingly, when the anti-peep function is needed, the magnetic privacy filter is adhered to the screen of the mobile device; while when the anti-peep function is not needed, the magnetic privacy filter can be detached from the mobile device instantly.