Gas discharge display device having plural groups of cathodes

A gas-discharge display device having an envelope at least part of which is a light-pervious material, a plurality of cathodes and at least one elongate common anode supported within said envelope, an ionizable medium within said envelope, the cathodes being arranged in a row extending substantially parallel to a said anode, said cathodes being spaced from said anode and being connected together in groups and each being operable to provide between the respective cathode and the anode a gas discharge visible through the light-pervious material, each said group comprising a respective elongate conductor, spaced portions of which constitute said cathodes, the conductors extending substantially coaxially around and along a common core which has an insulating surface, being of substantially the same shape and being substantially uniformly spaced so that the row of cathodes comprises a cyclic succession of said portions of all the conductors.