In one embodiment, a method for encoding or decoding a video signal includes constructing a base layer picture in a base layer, where the base layer picture includes image sample data. The columnar member provided on the lower frame not only determines the position of the liquid crystal panel with respect to the lower frame, but also determines the position of the optical sheet with respect to the lower frame and firmly holds the optical sheet onto the lower frame, thus preventing the disengagement of the optical sheet from the lower frame. Light is also conducted or transmitted through the light-conducting portion to the light-transmissive portion for highlighting an element, such as an edible or confection, that is in engaged to the light-conducting portion.