Display apparatus for elevator car

摘要

A display apparatus has a light modulator with an electrooptical Pockels cell disposed in a machine room to modulate a laser beam with a modulating signal from a signal source as determined by a piece of image information to be displayed. After its passage through an optical fiber, the modulated laser beam enters an elevator car where it is focussed on a horizontal deflector by a diminishing lens and then reflected to be focussed on a vertical deflector by a collecting lens. The focussed laser beam is collected on an inner surface of an elevator door by an objective lens. Each deflector is a galvanometer mirror attached to a coil and horizontally or vertically deflecting the laser beam through an angle proportional to a saw tooth current flowing through the coil under the control of the signal source. This results in the display of the piece of image information on the inner surface of the elevator door.