HMD

A head-mounted display (HMD) is a display device worn on the head that presents visual information in front of the user's eyes. HMDs are used to deliver virtual reality, augmented reality, or mixed reality experiences and may be self-contained or connected to external processors or sensors.

HMDs vary in how they blend real and synthetic imagery. Video see-through systems capture the real world via cameras and composite it with rendered content, while optical see-through devices use partially transparent optics to overlay synthetic images on the real scene. They may be monocular or binocular and can be tethered or standalone.

Technologies include microdisplays such as OLED or LCD panels, coupled with lenses or waveguides to form the image. Tracking relies on inertial sensors and external cameras or base stations to determine orientation and position. AR models often incorporate pass-through cameras and spatial mapping to anchor overlays in the environment.

Applications span consumer entertainment, professional training, design and prototyping, medical imaging, and remote collaboration. Notable examples include consumer VR headsets and enterprise AR glasses, such as the Microsoft HoloLens and various VR devices from Oculus and HTC.

The concept originated with early research in the 1960s. Ivan Sutherland's Sword of Damocles (1968) is widely cited as the first HMD, followed by decades of refinement. The modern consumer market emerged in the 2010s with more compact, higher-resolution devices and improved tracking. This technology remains central to virtual, augmented, and mixed reality applications.