You can already get add-on privacy filters for screens – indeed, Apple sells iPhone privacy protectors through its shop – but what the company describes in its filing is built into the screen itself. The patent was filed in June last year, but only made public by the U.S. Patent & Trademark Office (USPTO) on Thursday.

The filing, for “displays with adjustable angles-of-view,” describes two methods for blocking out prying eyes. The first involves a backlit screen that contains adjustable lenses, made of either liquid or liquid crystal. The second involves an “electrically controllable filter layer” that can darken parts of the screen.

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As noted by Apple Insider, the first publication to spot the filing on the USPTO website, the idea shows a need for countering the general trend towards wider viewing angles on screens. As the filing itself states: “In some situations, such as when a user of a laptop or other device with a display is using the device in public, the wide viewing angle is undesirable as it compromises privacy.”

Apple’s filing suggests a broad variety of possible applications for the privacy technology, ranging from laptops, phones and tablets to smart watches, earpieces, pendants and even “a device embedded in eyeglasses or other equipment worn on a user’s head.”