1. An electronic device for at least partially displaying a pixel of a displayable image comprising: a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity by optical interference; and, a charge-controlling mechanism to allow optical properties of the optical cavity to be varied by controlling a predetermined amount of charge stored on the first and the second reflectors, such that at least one of the visible wavelength and the intensity are variably selectable in correspondence with the pixel of the displayable image.