Computer giant Microsoft has revealed new wireless "hologram glasses" as part of its Windows 10 launch.

The company said it is now ready to merge real and virtual worlds through the use of holograms.

Called HoloLens, it said the device will be an evolutionary leap of technology, saying it is a computer "you wear".

A NASA expert, shown during a promotional video, said scientists will be using them within months to witness life on Mars through its Rover vehicle.

The event was held at its headquarters in Washington state.

"Welcomes to a new world of Windows, welcome to Windows Holgraphics," one speaker declared before the video explaining the system started.

"Holograms can become part of our everyday life."

Microsoft said there are now unlimited potential uses at home and at work.

It showed a staff member creating a virtual reality quad-copter in front of the audience, before a real HoloStudio 3D printer-built version of the design was flown briefly in the auditorium.

The new Spartan browser includes an ability to take screen snapshots, annotate them and save offline or share with other people.

It said the new operating system will be available as a free upgrade Windows 8, Windows 7 and Windows Phone users.

Greater capability will also be offered for users reading PDFs and other reading material which can be stored offline and made accessible to users' mobile devices.

The company said its new operating system would be available for new builds on its Insiders preview programme from next week.

Microsoft said the new browser will be made available to desktop browsers at first, with mobile versions coming later.

Meanwhile, the mobile virtual assistant Cortana will also be on the desktop, making users' desktops "smarter all the time".

Gamers are to get Xbox access on every Windows 10 device and improved energy efficiency will be available to extend mobile endurance time.

There will be inter-connectivity for gamers playing on mobile and X-Box machines.

Windows 10 will also allow Xbox One games to be streamed direct to tablet devices in their homes.

A cloud photo service will automatically check photos for duplicate photos and delete those that are unnecessary, and will auto-enhance shots to avoid redeye and under-exposure.

A showcase for the 84-inch Surface Hub was also revealed, with advanced new capabilities for One Note.

It said the fixed screen works like a tablet, making it ideal for business users.