Display

A display is an optical machine that conveys images or information by sending out visible light. It is often electronic, meaning it uses electricity as the power and the signaling.

A display can be a near-eye display fixed to the head, or a world-fixed display.

Displays work by being connected to a control system like a computer. The computer generates informational signals that the display reacts to and creates light. Displays are necessary for most modern computing.

There are two major types of display: World fixed display and head-fixed display. A world fixed display exists in the world, like a laptop, a TV, or a smartphone. A head fixed display is mounted to the head, meaning when you turn your head it stays in front of your eyes. Head fixed displays include VR headsets and the Google Glass and gadgets from Vuzix.

The most important features for a display to be useful are field of view, contrast (both static and dynamic and in color), and focal depth capability.

Common digital state machines include computers.

Traditional computer systems typically use 2D displays, which have a fixed focal depth.

Ray based gadgets are based on rays. These include heads up displays in cars.

By position

Head

VR headsets.

Eye

AR contact lens

By representation

Display gadgets can be point based, ray based, or interference based. Point and ray based displays can be studied using ray optics. Interference based displays must be examined using wave optics. Point based gadgets are based on point sources. These include laptop screens, televisions, and smartphone screens.

Interference pattern based

Interference based gadgets are also called holographic gadgets. The display gadget modulates light as in wave optics that interferes with itself and forms a pattern at some distance. This is the rarest type of device.