Patent ID: 7216992

Claim:
A reflective display device comprising a retroreflective layer including a plurality of unit structures that are arranged two-dimensionally on a virtual plane, and a modulating layer, which is arranged closer to a viewer than the retroreflective layer is and which is switchable between a first state and a second state that have mutually different optical properties, the reflective display device conducting a display operation by using light that has been reflected back from the retroreflective layer, wherein each said unit structure of the retroreflective layer has a recess defined by three planes that are opposed substantially perpendicularly to each other, and wherein an azimuthal direction, which is defined by projecting a normal to one of the three planes onto the virtual plane, and another azimuthal direction, which is defined by projecting an on-screen upward direction onto the virtual plane, form an angle of at most 30 degrees.