| 摘要 |
A display member comprising a housing having a chamber with a viewing face and a reference member movably mounted within said chamber to be movable into a first position in which one face of the member is in face to face contact with said viewing face and a second position in which the one face of the member is out of contact with the viewing face and the other face is in face to face with a rear face of the chamber spaced rearwardly from the viewing face, drive means being provided to produce an attractive and/or repulsive force between said housing and said member to move said member from said first or second position to the other position wherein no external drive means need be provided to maintain said member in said first or second position, an opaque fluid filling said chamber. |
