A method, comprising: forming a patterned layer of matrix material and/or one or more patterned layers of colour filter material in situ over a support film; forming in situ over said support film a stack of layers defining electrical circuitry via which each of an array of pixel electrodes is independently addressable; wherein forming said stack of layers comprises forming in situ over said patterned layer of matrix material and/or one or more patterned layers of colour filter material at least: a patterned conductor layer defining an array of source conductors and an array of drain conductors; a layer of semiconductor channel material defining semiconductor channels between the source and drain conductors; and another patterned conductor layer defining an array of gate conductors providing gate electrodes in said channel regions.