A glass composition for substrates having good polishability while securing characteristics for FPD substrates, especially for PDP substrates, from which a glass substrate having excellent polishing workability and productivity can be obtained, is provided. The nozzle assembly includes a pressure regulator and flow control element. In this state, during the non-display period, voltages are not applied to the optical shutter so that light emitted from the panel cannot transmit the optical shutter. Signals consisting of fourth data signal and of 180 degree out of phase equal amplitude inverse of said fourth data signal are transmitted together in two orthogonal linear polarities and at a 45 degree rotation from said third data signals. The or each electrode comprises a plurality of spaced electrically conductive elements to allow flexion of the electrode arrangement and electrically conductive material between the plurality of spaced electrically conductive elements to form a two-dimensional electrically conductive path across at least a portion of the first surface of the substrate.