A transflective display device (1, 1a - 1h) comprising: a set of pixels (2, 2a - 2h), wherein each of the pixels comprises a portion of bi-stable, phase change material, hereafter a PCM portion, having at least two reversibly switchable states, in which it has two different values of refractive index and/or optical absorption; one or more spacers, optically transmissive, and extending under PCM portions of the set of pixels; one or more reflectors, extending under the one or more spacers; an energization structure, in thermal or electrical communication with the PCM portions, via the one or more spacers; a display controller configured to selectively energize, via the energization structure, PCM portions of the pixels, so as to reversibly switch a state of a PCM portion of any of the pixels from one of its reversibly switchable states to the other; a backlight unit, configured in the device to allow illumination of the PCM portions through the one or more spacers; and a backlight unit controller, configured for modulating one or more physical properties of light emitted from the backlight unit, characterized in that: the backlight unit is an edge backlight unit, arranged in the device to illuminate the PCM portions from a lateral side of the device, via one or more waveguides, wherein the waveguides extend, each, in a same plane that is parallel to an average plane of the one or more reflectors; said one or more reflectors comprise a reflective layer that extends under the one or more spacers; the one or more waveguides are configured as a waveguide extending below said reflective layer, opposite to the one or more spacers with respect to said reflective layer; and the device further comprises optical structures, arranged in or on the reflective layer, or in a vicinity thereof, the optical structures arranged with respect to the pixels so as to allow light emitted from the backlight unit and internally reflected in said waveguide to exit toward a PCM portion of each of the pixels. a set of pixels (2, 2a - 2h), wherein each of the pixels comprises a portion of bi-stable, phase change material, hereafter a PCM portion, having at least two reversibly switchable states, in which it has two different values of refractive index and/or optical absorption; one or more spacers, optically transmissive, and extending under PCM portions of the set of pixels; one or more reflectors, extending under the one or more spacers; an energization structure, in thermal or electrical communication with the PCM portions, via the one or more spacers; a display controller configured to selectively energize, via the energization structure, PCM portions of the pixels, so as to reversibly switch a state of a PCM portion of any of the pixels from one of its reversibly switchable states to the other; a backlight unit, configured in the device to allow illumination of the PCM portions through the one or more spacers; and a backlight unit controller, configured for modulating one or more physical properties of light emitted from the backlight unit, characterized in that: the backlight unit is an edge backlight unit, arranged in the device to illuminate the PCM portions from a lateral side of the device, via one or more waveguides, wherein the waveguides extend, each, in a same plane that is parallel to an average plane of the one or more reflectors; said one or more reflectors comprise a reflective layer that extends under the one or more spacers; the one or more waveguides are configured as a waveguide extending below said reflective layer, opposite to the one or more spacers with respect to said reflective layer; and the device further comprises optical structures, arranged in or on the reflective layer, or in a vicinity thereof, the optical structures arranged with respect to the pixels so as to allow light emitted from the backlight unit and internally reflected in said waveguide to exit toward a PCM portion of each of the pixels. the backlight unit is an edge backlight unit, arranged in the device to illuminate the PCM portions from a lateral side of the device, via one or more waveguides, wherein the waveguides extend, each, in a same plane that is parallel to an average plane of the one or more reflectors; said one or more reflectors comprise a reflective layer that extends under the one or more spacers; the one or more waveguides are configured as a waveguide extending below said reflective layer, opposite to the one or more spacers with respect to said reflective layer; and the device further comprises optical structures, arranged in or on the reflective layer, or in a vicinity thereof, the optical structures arranged with respect to the pixels so as to allow light emitted from the backlight unit and internally reflected in said waveguide to exit toward a PCM portion of each of the pixels.