US Patent 7370987 Display panel comprising a light guide plate

The display panel (21) comprises a light guide (2), a second plate (4) and a movable element (3) between both plates for locally decoupling light out of the light guide (2). Voltages, applied to electrodes (5,6 resp. 25), associated with the light guide (2), the second plate (4) and the movable element (3), locally bring the movable element (3) into 5 contact with the light guide plate (2) or the second plate (4). If, between the light guide (2) and the first electrodes (5) a layer (51) is present with a second refractive index being smaller than the first refractive index of the light guide (2), and the light guide (2) is positioned between the first electrodes (5) and the movable element (3), absorption of the light transported through the light guide plate (2) is reduced, providing a display panel (21) with 10 improved power efficiency.