Patent ID: 8226255

Claim:
A button, comprising: a keycap made of transparent material, and the keycap comprising a first side surface and a second side surface opposite to the first side surface; four light guide blocks set on the first side surface of the keycap; four ultraviolet lighting elements to emit ultraviolet light, each ultraviolet lighting element set adjacent to a corresponding one of the at least one light guide block, wherein ultraviolet light emitted by the at least one ultraviolet lighting element enters into the corresponding light guide block, then is reflected by the light guide block to pass through the keycap to arrive at the second side surface of the keycap; wherein a depressed portion is defined in the first side surface of the keycap, the light guide blocks and the ultraviolet lighting elements are set on a bottom of the depressed portion; the keycap is generally quadrate-shaped; the four lighting elements are adhered on four corners of the bottom of the depressed portion, and each of the light guide blocks is arranged between two adjacent lighting elements.