Optical head-mounted display

A Google Glass wearer

Optical head-mounted display (OHMD) is a wearable device that has the capability to reflect projected images as well as allow the user to see through it or see better with it. Typically, an OHMD is used in augmented reality (AR) systems, allowing for the overlay of digital information onto the real world, enhancing the user's perception of reality with digital content. This technology is also fundamental in the development of virtual reality (VR), where it can create immersive environments for the user.

Overview

An optical head-mounted display consists of a display unit, usually one for each eye, which projects images directly or indirectly to the wearer's field of vision. Some models use transparent displays that allow for augmented reality, overlaying digital content onto the real world. Others use opaque displays to create a fully immersive virtual reality experience. The technology behind OHMDs includes various optical techniques such as waveguides, prisms, and holographic elements to direct the images into the eyes.

Applications

OHMDs have a wide range of applications across different fields. In the military, they are used for advanced navigation and situational awareness. In medicine, they assist in complex surgical procedures by providing real-time data and 3D visualizations. In education, they offer immersive learning experiences. Additionally, in the entertainment industry, OHMDs are used in video gaming and interactive media to provide a deep level of immersion.

Key Technologies

The development of OHMDs relies on several key technologies:

• Display Technology: Liquid Crystal Displays (LCD), Organic Light-Emitting Diodes (OLED), and Light Emitting Diodes (LED) are commonly used for image projection.
• Optics: Advanced optics are essential for miniaturizing the components and providing a clear, wide field of view. Techniques include the use of waveguides and Fresnel lenses.
• Tracking Systems: To provide a seamless experience, OHMDs incorporate tracking systems that monitor the user's head movements and adjust the image accordingly. This can include gyroscopes, accelerometers, and camera-based tracking.

Challenges and Future Directions

While OHMDs offer significant potential, there are challenges to overcome, including miniaturization of components, reducing power consumption, and improving user comfort. Future directions in OHMD technology may focus on enhancing the display resolution, expanding the field of view, and integrating more advanced sensors for better interaction with the digital content.

See Also

• Wearable technology
• Mixed reality
• Human-computer interaction
• Smartglasses