A set-top box is configured to mount therein a security device which stores security information on a broadcasting entity, and extracts transmission information for receiving a broadcasting signal modulated from a control signal from a head end. Generally the invention has a frame clip and a spring clip. The partition wall of the macrovoid layer has a thickness of from 0. Another optical device is a display apparatus which uses a diffusely reflecting polarizer layer in combination with a turning lens which folds shallow angle light toward a light modulating layer.