Keyboard

The invention relates to a keyboard which comprises the components of a plurality of buttons, a base board and a backlight module. Furthermore each button comprises a key cap with a first projection, and a sliding part with a second projection. The first projection is provided with a first inclined surface. The second projection is provided with a second inclined surface. Furthermore the first inclined surface is parallel with the second inclined surface. When the key cap is pressed and moves in a direction to the base board, the first inclined surface moves along the second inclined surface, thereby pushing the sliding part to horizontally move relative to the base plate, so that light beam which penetrates through the through hole of the base plate is emitted out through the key cap through the sliding part or is blocked by the sliding part.