Physical barriers (210) are present between neighbouring pixels (200) on a circuit substrate (100) of an active-matrix electroluminescent display device, particularly with LEDs (25) of organic semiconductor materials. In order to reduce parasitic capacitance in the circuit substrate, the invention forms these barriers (210) with metal or other electrically-conductive material (240) that provides at least part of the signal lines (160) at a higher level than the circuit substrate (100). This conductive barrier material (240) is connected to the matrix circuitry within the substrate (100) but is insulated (40) at least at the sides adjacent to the LEDs (25). Preferably, an inter-capacitance guard line (9) is included in the circuit substrate (100) between the signal lines (160) and the circuitry in the substrate (100).