Patent attributes
A system, such as a head-mounted display (HMD), displays images to a user. The system has an active state and an idle state. The system includes a display device, a beam combiner, and a user-operated control. The display device displays images when the system is in the active state and emits a reduced amount or no light when the system is in the idle state. The beam combiner provides a first optical path for light from an external environment to the user's eye and also provides a second optical path for light emitted from the display device to the user's eye. Responsive to activation by the user, the control switches the system between states that include the active state and the idle state, where the idle state is a default state and the system remains in the active state only while the user-operated control remains activated by the user.