News: Apple has been granted a patent for a wireless headset that mounts an iPhone in front of the eyes, hinting at the company's expansion into virtual reality.

Apple's patent, which gained approval yesterday, is for a "head-mounted display apparatus for retaining a portable electronic device with display".

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The headset looks and is worn like an oversized pair of sunglasses. A portable device, illustrated as the tech giant's ubiquitous iPhone, slots into a rectangular gap in the frame where the lenses would be so its screen is placed directly in front of the eyes to present image-based media.

"The portable electronic device may be operatively coupled to the head-mounted device such that the portable electronic device and head mounted device can communicate and operate with one another," said the patent abstract.

Worn this way, the smartphone could become a virtual reality headset and compete with similar devices such as Oculus Rift, Google's Cardboard and Samsung's Gear VR.

Virtual reality is designed to immerse the user in a digitally created environment, using imagery that covers the wearer's entire field of vision.

The document, US patent 8,957,835, continues: "There is provided a method for displaying image based content on a head-mounted device... The method may also include adjusting the image based content displayed on the screen for close up viewing."

Controls on the headset could be used to alter functions such as brightness and volume, or to switch between displays.

The headset could also include a battery to extend the viewing time, a cooling system to prevent overheating and extra memory for storing large image-based files.

Details of the potential inclusion of microphones, speakers and cameras in the headset are also outlined in the patent.

Virtual reality is becoming increasingly popular and major technology companies are all hoping to cash in on the surge in interest.

Last year, Google released its cardboard headset that also holds a smartphone in front of the eyes in a similar way to Apple's proposal.

Facebook has acquired the company that designed Oculus Rift for $2 billion, not long before Oculus VR was sued by video games developer ZeniMax Media.

In a recent interview interview with the New Yorker, Apple's senior vice president of design Jonathan Ive said the face "was the wrong place" for technology.