An active matrix type display device is realized by integrally forming pixel electrodes and switching thin film transistors. The display device has a panel structure formed by a pair of substrates bonded to each other with a predetermined gap separating them and a liquid crystal layer held in the gap between the pair of substrates. A set of thin film transistors, a planarizing film covering said thin film transistors and a set of pixel electrodes arranged on the planarizing film are formed on one of the substrates, whereas an opposite electrode is formed vis-a-vis the set of pixel electrodes on the other substrate. The planarizing film of the display device is made of a photosensitive material and formed to have a varying thickness in the first substrate by means of an exposure process. The parts of the planarizing film that correspond to the pixel electrodes have a thickness that is made to vary according to the wavelength of the display colour assigned to each of the pixel electrodes.