A method for controlling a light emitting diode is provided. In addition, a number of masks is reduced to save the cost and at the same time minimize or reduce a layout area. The side surfaces of the PZT elements are then coated with a layer of a material which promotes crystallisation of the PZT, such as one having a high concentration of PZT crystallisation centres, and a PZT annealing step is carried out. For example, the items can be products represented in an electronic catalog, web pages or other documents accessible on a network, or web sites.