A display device (1, 1a - d), comprising: a set of pixels, each having a layer structure that includes: a bi-stable, phase change material , or bi-stable PCM, having at least two reversibly switchable states, in which the PCM exhibits two different values of refractive index and/or optical absorption; and a heating element , in thermal communication with the PCM in the layer structure ; a controller configured to energize any of the pixels in order to energize a respective heating element and in turn reversibly change a refractive index and/or an optical absorption of a respective PCM ; and characterised in that the display device further comprises: a set of nonlinear, monostable resistive switching elements , each in electrical communication with the heating element of one of the pixels, and designed so as to exhibit: a low resistance, unstable state, which allows the heating element to be energized via the resistive switching element , so as to heat the PCM and reversibly change a refractive index and/or an optical absorption thereof, in operation; and and a high-resistance, stable state, which allows leakage currents to be mitigated, so as to prevent inadvertent switching of the PCM from one of its states to the other, in operation; and the heating element is electrically insulated from the PCM ; and the controller is configured to energize any of the pixels via a respective one of the resistive switching elements , so as to switch the latter from its high-resistance state to its low resistance state, in order to energize a respective heating element . a bi-stable, phase change material , or bi-stable PCM, having at least two reversibly switchable states, in which the PCM exhibits two different values of refractive index and/or optical absorption; and a heating element , in thermal communication with the PCM in the layer structure ; a controller configured to energize any of the pixels in order to energize a respective heating element and in turn reversibly change a refractive index and/or an optical absorption of a respective PCM ; a set of nonlinear, monostable resistive switching elements , each in electrical communication with the heating element of one of the pixels, and designed so as to exhibit: a low resistance, unstable state, which allows the heating element to be energized via the resistive switching element , so as to heat the PCM and reversibly change a refractive index and/or an optical absorption thereof, in operation; and and a high-resistance, stable state, which allows leakage currents to be mitigated, so as to prevent inadvertent switching of the PCM from one of its states to the other, in operation; and a low resistance, unstable state, which allows the heating element to be energized via the resistive switching element , so as to heat the PCM and reversibly change a refractive index and/or an optical absorption thereof, in operation; and and a high-resistance, stable state, which allows leakage currents to be mitigated, so as to prevent inadvertent switching of the PCM from one of its states to the other, in operation; and the heating element is electrically insulated from the PCM ; and the controller is configured to energize any of the pixels via a respective one of the resistive switching elements , so as to switch the latter from its high-resistance state to its low resistance state, in order to energize a respective heating element . <EOS>