VR headset

A VR headset: An Oculus Rift CV1

A VR headset is a head-mounted device that immerses the user in a computer-generated environment. It uses near-eye displays and positional tracking. An example is the Oculus Quest 2.

VR headsets are either standalone gadgets or they have to be tethered to a computer.

VR headsets are widely used with VR video games, but they can be used in other applications, including simulators and trainers.

VR headsets typically include a biscopic display, stereo sound, and sensors like accelerometers and gyroscopes for tracking the pose of the user's head. VR headsets typically use at least one MEMS IMU for 3DOF motion tracking, and optionally more tracking technology for 6DOF motion tracking. 6DOF gadgets typically use a sensor fusion algorithm to merge the data from the IMU and any other tracking sources. The sensor fusion algorithms that are used are often variants of a Kalman filter.

Some VR headsets also have eye-tracking sensors. The VR glasses use a technology called head-tracking, which changes the field of vision as a person turns their head. Some implementations of the technology have latency if the head moves too fast.

Virtual reality headsets and viewers have also been designed for smartphones. Unlike headsets with integrated displays, these units are essentially enclosures which a smartphone can be inserted into.

A VR headset's mass can cause mass imbalance when a user turns his head. When turning the head left or right, it is more efficient to have something clamping the sides of the head like headphones, rather than on the back and front, if you want to transfer the rotational momentum.

Building

A VR headset is classically a display or two displays that give a flat image, with a biconvex nonequiconvex lens for each eye.

The displays are typically LCD or OLED that connect with MIPI DSI to a driver board.

A headset that uses electromagnetic 3D tracking must be built to have no large metal on it, because that will interfere with the 3D tracking. Oculus Rift DK1 and DK2 both interfere with electromagnetic tracking systems. The HTC Vive interferes minimally.

The Relativty is an example of an open source VR headset, but it requires buying a display driver board and displays combo kit from unreliable sources.

To build a varifocal headset, the display and lens must be mounted on a stage, and that stage must move closer and further from the eye.

Google Cardboard is a good basis for building a headset.

Smartphone screens with MIPI DSI are a good basis for building a headset.

TI's DLP line may be a good fit. TI is set to announce new DLP chipsets at extremely high frame rates in the year +2024.

History

VPL Research was a company that made early VR headsets in the 1980s.

The PSVR headset for the PlayStation 4 video game console, released in the year +2016

The Sega VR was announced in the year +1991 and seen in early 1993 at the Winter CES. It was never released for consoles, but was utilized for the Sega VR-1 motion simulator arcade attraction in the year +1994. Another early VR headset, the Forte VFX1, was announced at CES in the year +1994. The VFX-1 has stereoscopic displays, 3-axis head-tracking, and stereo headphones.

Sony released the Glasstron in the year +1997, which has an optional positional sensor, allowing the wearer to view the surroundings, with the perspective moving as the user's head moves, giving a deep sense of immersion. These VR headsets gave MechWarrior 2 players a new visual perspective of seeing the battlefield from inside the cockpit of their craft. However, these early headsets failed commercially due to their limited technology, and they were described by John Carmack as like "looking through toilet paper tubes".

In the year +2012, a crowdfunding campaign began for a VR headset known as Oculus Rift; the project was led by several prominent video game developers, including John Carmack who later became the company's CTO. In March 2014, the project's parent company Oculus VR was acquired by Facebook for $2 billion. The final consumer-oriented release of Oculus Rift began shipping on 28 March 2016.

In March 2014, Sony demonstrated a prototype headset for PlayStation 4, which was later named PlayStation VR. In the year +2014, Valve demonstrated some headset prototypes, which led to a partnership with HTC to produce the Vive, which focuses on "room scale" VR environments that users can naturally navigate within and interact with. The Vive was released in April 2016 and PlayStation VR in October 2016.

Google released a series of specifications and associated DIY kits for virtual reality viewers known as Google Cardboard; these viewers are capable of being constructed using low-cost materials (and a smartphone with a gyroscope), such as cardboard (hence the naming). Samsung Electronics partnered with Oculus VR to co-develop the Samsung Gear VR (which is only compatible with some Samsung Galaxy gadgets). LG Electronics developed a headset with dedicated displays for its LG G5 smartphone known as LG 360 VR.

In the year +2019, Oculus and PlayStation VR had a majority position in the VR headset market.

In June 2019, Valve released their own headset, the Valve Index, without a partnership with HTC.

Technology

Resolution and display quality

There are different optics and visual qualities that affect how an individual perceives the image quality and how they experience the virtual world. The image clarity depends on the display resolution, optic quality, refresh rate, and field of view.

Because virtual reality headsets stretch a single display across a wide field of view (up to 110° for some gadgets according to manufacturers), the magnification factor makes flaws in display technology much more apparent. One issue is the so-called screen-door effect, where the gaps between rows and columns of pixels become visible, kind of like looking through a screen door. This was especially noticeable in earlier prototypes and development kits, which had lower resolutions than the retail versions.

Optics

The lenses of a headset are responsible for mapping the up-close display to a wide field of view, while also providing a more comfortable distant point of focus. One challenge with this is providing consistency of focus: because eyes are free to turn within the headset, it is important to avoid having to refocus to prevent eye strain.

Fresnel lenses are commonly used in virtual reality headsets due to their compactness and lightweight structure. The lenses do not use multiple pieces of material in their lenses like other lenses, but the lens will be broken down into sections, allowing the individual to have a wider range of view. The issue seen with the lens consists of seeing the ridges of the lenses when the headset is not properly aligned on the head.

The lenses introduce distortion and chromatic aberration, which are typically corrected in software. The lenses can also be adjusted dynamically to account for a user's eyeglass prescription so that the user can use the headset without corrective eyeglasses.

Latency requirements

Virtual reality headsets have significantly higher requirements for latency—the time it takes from a change in input to have a visual effect—than ordinary video games. If the system is too sluggish to react to head movement, then it can cause the user to experience virtual reality sickness, a kind of motion sickness. According to a Valve engineer, the ideal latency would be 7-15 milliseconds.

A VR headset must be connected to a graphics processing unit (GPU) that has enough computational capability to render a large number of frames in a small amount of time. Oculus cited the limited processing power of Xbox One and PlayStation 4 as the reason why they targeted the PC gaming market with their first gadgets.

Some VR headsets can work by using foveated rendering.

See also

• Augmented reality headset
• Curved screen
• List of virtual reality headsets
• Mixed reality