Patent ID: 7870686

Claim:
A method of installing a subway tunnel light box in a subway tunnel for displaying a back-lighted image to a viewer inside of a subway car traveling in the subway tunnel, comprising the steps of: choosing a transparent video display that is mounted in the light box; calculating a perceived horizontal viewing angle for a typical viewing distance of the subway tunnel light box installed at a preselected location in the subway tunnel by a viewer in the subway car based upon a physical height of the transparent video display and a desired aspect ratio of a perceived image for the transparent video display; determining a number of images to be displayed on the transparent video display with an acceptable horizontal image resolution for each of said perceived images; positioning a narrow light source in the subway tunnel light box behind each of the displayed images so that each of the displayed images is illuminated by an associated narrow light source with an associated narrow light source horizontal illumination angle substantially the same as the perceived horizontal viewing angle; and installing the subway tunnel light box at the preselected location.