A display device is disposed within a casing of an electronic device. The display device includes a display part, at least one light source, a projection part and an imaging structure. The display part is disposed on the casing and exposed outside. The at least one light source is disposed within the casing, and emits at least one light beam. The projection part is arranged between the at least one light source and the display part, and has an image region. After the at least one light beam passes through the projection part, a projection pattern corresponding to the image region is generated. The imaging structure is disposed on the display part. The imaging structure receives the projection pattern, so that the projection pattern is shown on the display part.