Abstract: A keyboard includes a transparent board, keyswitches, and a backlight module. The keyswitches could move upward and downward relative to the transparent board. At least one keyswitch includes a cap and a light exciting layer disposed in a transparent concave portion of the cap. The backlight module is disposed under the transparent board and includes a blue-light emitting diode, a reflection sheet, and a light guide plate having a light entrance surface, a light exit surface, and a bottom surface. The blue-light emitting diode is disposed corresponding to the light entrance surface for emitting light into the light guide plate. The reflection sheet is disposed on the bottom surface for reflecting light in the light guide plate to emit out of the light exit surface and then pass through the transparent board and the transparent concave portion, so that the light exciting layer could be excited to emit light.

Abstract: A method for manufacturing a light guide includes providing a roll unit, enclosing a metallic film around the roll unit wherein the metallic film has a plurality of micro-protrusions, driving a light guide film to pass through the roll unit to form a plurality micro-indentations on the light guide film, and cutting the light guide film to have a determined size to form a light guide. Thus, the light guide is made by hot rolling so that the light guide is made easily and quickly. In addition, only the surface of the light guide film is heated and softened so that after the light guide film is hot rolled by the roll unit, the light guide film is cooled and solidified quickly to prevent the light guide film from being deformed due to an excessive heat.