| 摘要 |
A subway tunnel light box for displaying a back-lighted image to a viewer inside of a subway car traveling in the subway tunnel in which a transparent video display for displaying a number of images, such as an LCD, is mounted in the light box and a narrow light source, preferably having a width of one pixel, is positioned in the box behind each of the images at a distance less than a typical viewing distance so that each image is illuminated by an associated narrow light source with an associated narrow light source horizontal illumination angle substantially the same as a preselected perceived horizontal viewing angle calculated for the typical viewing distance based upon a physical height of the transparent video display and a desired aspect ratio of a perceived image.
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