Patent ID: 7581342

Claim:
A display device that is capable of selectively displaying a first display contents and a second display contents where the first display contents and the second display contents have first overlapped parts overlapped with each other, the display device comprising: an ultraviolet light source for emitting ultraviolet light; a color light source for emitting color light; and a filter that is arranged in front of the ultraviolet and color light sources so that a rear surface of the filter can be selectively hit by the ultraviolet light and the color light, wherein the filter has a first area part for displaying the first display contents excluding the first overlapped parts when the ultraviolet light is emitted, a second area part for the second display contents excluding the first overlapped parts when the color light is emitted, and a third area part for displaying the first overlapped parts when one of the ultraviolet light and the color light is emitted, wherein the first area part blocks the color light and produces visible light when the ultraviolet light hits the first area part, the second area part allows the ultraviolet light and the color light to pass therethrough, and the third area part allows the ultraviolet light and the color light to pass therethrough and produces visible light when the ultraviolet light hits the third area part.