A patent filed by Microsoft on January 30, 2012, and this week made available to the public, outlines a series of head-mounted display devices and their potential gaming applications.

The filing (spotted by a NeoGAF user), dubbed "Multiplayer gaming with head-mounted display," describes "a system and related methods for inviting a potential player to participate in a multiplayer game via a user head-mounted display device…In one example, a potential player invitation program receives user voice data and determines that the user voice data is an invitation to participate in a multiplayer game. The program receives eye-tracking information, depth information, facial recognition information, potential player head-mounted display device information, and/or potential player voice data."

The patent alludes to a reference design (subject to change) that may include transparent or partially transparent displays that sit in front of a user's eyes in the form of traditional glasses. The patent filing includes a range of potential device scenarios, including the use of Organic Light-Emitting Diode (OLED) displays, eye scanning, microphones, and gyroscopic and accelerometer sensors to determine user head and body positioning when worn.

"The HMD device may include an eye-tracking system that utilises at least one inward-facing sensor. The inward-facing sensor may be an image sensor that is configured to acquire image data in the form of eye-tracking information from a user's eyes. Provided the user has consented to the acquisition and use of this information, the eye-tracking system may use this information to track the position and/or movement of the user's eyes. The eye-tracking system may then determine where and/or at what person or object the user is looking. In another example, the inward-facing sensor may capture retinal scan information from a user's retina. Provided the user has consented to the acquisition and use of this information, such information may be used to identify the user wearing the HMD device."

Outward-facing sensors would also detect the environment of the wearer, locate users sharing the space, and track gestures performed by the wearer. Numerous mentions of "time-of-flight depth camera" systems also draw parallels with similar technology included in the updated Kinect 2.0 that will ship alongside the upcoming Xbox One console. These could be used to scan the space before determining which games may be the most appropriate for the given play space.

"The HMD device may also include an optical sensor system that utilises at least one outward-facing sensor, such as an optical sensor. Outward-facing sensor may detect movements within its field of view, such as gesture-based inputs or other movements performed by a user or by a person within the field of view. Outward-facing sensor may also capture image information, such as facial recognition information, and depth information from a physical environment and real-world objects within the environment. For example, outward-facing sensor may include a depth camera, a visible light camera, an infrared light camera, and/or a position-tracking camera."

The potential inclusion of three accelerometers and three gyroscopes would allow for head-positioning tracking, not unlike the technology found in the Oculus Rift.

"Motion sensors may also be employed as user input devices, such that a user may interact with the HMD device via gestures of the neck and head, or even of the body."

Voice controls, with a focus on natural speech, are mentioned throughout the filing. The HMD may include one or more microphones, and be used to input commands and requests, such as when instigating a multiplayer game with another user.

"In other examples, audio may be presented to the user via one or more speakers on the HMD device. Such audio may include, for example, music, instructions, and/or other communication from the multiplayer game program, the potential player invitation program, or other sources."

The filing also lists provisions for users to toggle the amount of personal information shared by the device with other users, from limited privacy modes showing user IDs and game achievements, all the way to exchanging personal information, such as game interests.

While only a single device appears to be wearable per user, the report includes information on multiple head-mounted displays being used in conjunction with each other, either to view other matches in progress or join games with multiple participants.

The technology and accompanying diagrams and descriptions in the patent share some striking similarities with images shown previously in a purportedly leaked document, prior to the Xbox One announcement. The information was later taken down at the request of Microsoft.