Recently, green technologies have been taken as an important issue for the sustainable development due to environmental consciousness. In general, to fit the requirements of Eco-Display in terms of backlight modules, we use the LED as the source of backlight and modulate the viewing angles to increase the efficiency of outgoing rays from backlight. Conventional viewing angle modulation can be achieved by two ways, including a dual light source system and a dual liquid crystal layers design. But multiple optical structures make them face some problems about energy saving. In this study, we take advantage of conventional side-it configuration, which enables viewing angle modulation by the design of simultaneous multiple surface lens and a light guide plate. The proposed mechanism would confine the viewing angles of backlight module to get the purpose of directional backlight.