GB1349904A - Fixed notice boards for viewing from passing vehicles - Google Patents

Abstract

1349904 Display device M A JOHNSON 8 Nov 1971 [30 June 1971] 30541/71 Heading G5C A series of louvred screens 9 having converging plates are placed between a series of display panels 6 and an observer, so that, when the observer moves past the panels, the plates restrict a full view of an image on each panel to a period of travel when the viewer's line of sight is substantially at right angles to the panel. Subsequent images give the appearance of a single picture through persistence of vision. Each panel 6 may be lit by a light source 7 and the plates of the louvred screen may be located at an acute angle relative to the panel to compensate for the direction of travel of the observer, Fig. 6b (not shown). The panels and louvred screens may be located on the side of the tunnel of an underground train, Fig. 1 (not shown). In order to exclude the pattern of plates in a screen 9 from the concurrent images seen by the viewer, consecutive images may be indexed so that each screen is placed in a different position relative to the image.