GB1353821A - Variable display devices - Google Patents

Abstract

1353821 Animated displays R L CLOUTIER 6 May 1971 [7 May 1970] 13569/71 Heading G5C A display device comprises a mass of fine, dry, rigid particles including at least two groups, those of the second group having physical characteristics not possessed by the first group, the particles tending to remain in their own groups when the device is moved manually or mechanically. The particles may be of four different types 21 to 24 contained between glass plates 18, 19. Particles 21 are NaCl crystals, particles 22, 23 are glass beads and particles 24 are glass microballoons. Upon agitation of the device, different flow patterns are produced, enhanced by different colours applied to the four different particle groups or classes. The device may be illuminated by light transmission or reflection, Fig. 5 (not shown). One or more particle classes may have fluorescent coatings, in which case ultraviolet light may be used. The particles may be coated with a heatactivatable adhesive material so that the particles, although initially dry, may be caused to adhere after a particular design is obtained, and hence the design becomes fixed. In alternative embodiments, Figs. 4 and 6 (not shown), the glass plates may be in the form of a circular and convex disc, or in the form of concentric cylinders with an axial source of illumination. If one class of particles is magnetic, e.g. iron filings, a magnet may be externally applied to provide an additional means for changing the pattern. A light may be shone through the device to provide an image which may be projected on a screen, e.g. by the use of a standard projector. Alternatively the device in disc form, Fig. 4 (not shown), may be placed in a projector and rotated to project a varying image.