Abstract: The invention concerns an improvement in a display member of the type comprising a plurality of reference members (14) accommodated within a common chamber (11) filled with an opaque fluid wherein each reference member is independently movable between a display position at which it is in face to face engagement with a display face (12) of the chamber (11) and a non-display position at which it is out of engagement with the display face. The improvement comprises each reference member (14) being associated with a boundary wall (19) which surrounds the sides of the reference member when at its non-display and/or display position. The function of the boundary wall (19) is to direct fluid entering or escaping from the space between the reference member and a face of the chamber adjacent the boundary member.

Abstract: A display member (10) comprising a housing (14) having a chamber (12) with a viewing face (16) and a lamina member (24) movably mounted within the chamber (12) to be movable into a first position in which one face (26) of the member (22) is in face to face contact with the viewing face (16) and a second position in which the one face (26) of the member (24) is out of contact with the viewing face (16) and the other face (25) is in face to face with a rear face (15) of the chamber (12) spaced rearwardly from the viewing face (16), a drive (22,20) being provided to produce an attractive and/or repulsive force between the housing (14) and the member (24) to move the member (24) from the first or second position to the other position wherein no external energy need be provided to maintain the member (24) in the first or second position, an opaque fluid filling the chamber.

Abstract: A display member (10) comprising a housing (14) having a chamber (12)with a viewing face (16) and a lamina member (24) movably mounted within said chamber (12) to be movable into a first position in which one face (26) of the member (22) in face to face contact with said viewing face (16) and a second position in which the one face (26) of the member (24) is out of contact with the viewing face (16) and the other face (25) is in face to face with a rear face (15) of the chamber (12) spaced rearwardly from the viewing face (16), drive means (22, 20) being provided to produce an attractive and/or repulsive force between said housing (14) and said member (24) to move said member (24) from said first or second position to the other position wherein no external drive means need be provided to maintain said member (24) in said first or second position, an opaque fluid filling said chamber.