| 摘要 |
A display device which is at least one metre in diameter includes superimposed light-transmitting walls (10 -13) defining intervening chambers (18 - 20) containing two immiscible fluids having different densities. One of the fluids is a coloured liquid and the other fluid (21) is a substantially colourless gas. The walls are mounted for rotation, and each chamber includes projections (30) forming cup-shaped recesses (31) at the periphery of each chamber which collect gas at the top of the chamber and release it into the liquid. The superimposed walls (10 -13) are separated by spacer rings (14 -16) containing evacuation ports (51 - 53) through which a proportion of the gas has been removed. The pressure of the gas is thus reduced below atmospheric pressure such that the external pressure acting on the walls at least partially counteracts the weight of coloured fluid acting outwardly on the walls. The evacuation ports (51 - 53) may be permanently re-sealed or provided with non-return valves. |
