Search giant Google has patented the design of its augmented-reality glasses, known as Project Glass.
Three patents for a "wearable display device" with characteristics of the much-talked about futuristic glasses were submitted last autumn.
The patents reference such functions as displaying data in front of the wearer's eyes and playing audio.
In April, Google revealed details of its research into the glasses and showed a demo video of a prototype .
The patents show images of different versions of augmented reality glasses, some with lenses and some without.
Google is working on the project in its research lab, Google X.
The prototypes are currently being tested by the firm's executives, including Sergey Brin and Vic Gundotra.
The demo video showed science fiction-like glasses equipped with a microphone and partly transparent tiny screen right above the user's right eye.
Besides displaying information about the wearer's surroundings, the glasses were shown to be used to communicate with other people, browse the web, listen to music and also take photos.
There are other firms researching the augmented-reality eyewear.
For instance, Oakley is currently developing similar glasses targeted at athletes and other sportsmen and women.
A number of companies had attempted to pioneer the concept as well, but did not get very far because their versions required users to carry separate battery equipment, as analyst at Davies Murphy Group Europe told the BBC in an earlier interview.
"There are huge opportunities for tailored advertising with augmented reality systems - especially if they have in-built GPS location tracking," Chris Green said.
"The monetisation opportunities would be enormous - but there are still big issues involved with shrinking the technology and making the computer that receives and processes the data truly portable."