Displays are our main source for information and often interaction. Augmented reality and associated technologies are delivered to the user through a display or projection device of some type, and at some distance. It can be (is) different for all cases.
Displays can be in three different locations, far (signage, billboards, annunciators, command and control, conference rooms, CAVEs, (Cave Automatic Virtual Environments ), etc.), near (computers, in-vehicle dashboard/cockpit, TV, etc.), and close (wearables—e.g., head-mounted displays, watches, etc.). Near-displays are sub-divided into lean-back and lean-forward. Lean-back is TV viewing, and lean-forward is computer viewing. Cockpit and in-vehicles displays are lean- forward, because like a computer they are typically involved with some form of interactivity.
Close displays are sub-divided into four primary categories, Virtual reality (virtual reality) head-mounted displays (HMDs), augmented-reality displays (helmets, and glasses), handheld devices such as a smartphone or tablet, and personal media player (PMP) or devices (PMD) primarily for entertainment, although can also be used for business. A fifth category could be contact lenses and implants.