BACK LIGHTING APPARATUS FOR KEYPAD ASSEMBLY

摘要

A backlight apparatus for a keypad assembly is provided to enable a sub light emitting unit to allow the light of LEDs to proceed more than a predetermined distance away from the LEDs and be emitted, thereby emitting the entire keypad to improve a use of the keypad. A backlight apparatus for a keypad assembly comprises a keypad(20), plural LEDs(Light Emitting Diodes)(30), a waveguide sheet(40), a PCB(Printed Circuit Board), and at least one sub light emitting unit(100). The plural LEDs are equipped in the side of the keypad to emit light. The waveguide sheet emits the light of the LEDs to the keypad. The PCB has the LEDs and plural dome switches. An end of the at least one sub light emitting unit is positioned near the LEDs. The other end of the at least one sub light emitting unit is positioned away from a predetermined distance along the circumference of the waveguide. The at least one sub light emitting unit allows the light to be incident in the initial position of the end, proceed to the inside, and be emitted in a close position at a predetermined distance to make the waveguide sheet emitted.