| 摘要 |
A keypad assembly is provided to illuminate regularly an overall area of a keypad by using relatively a few light emitting elements by using an optical waveguide which can guide light to a keypad and selectively output light to only a part of the keypad which needs illumination. A keypad assembly comprises plural key buttons(20), plural light emitting elements(30), a light waveguide(40), plural reflection patters(50) and an assistant layer(60). The plural light emitting elements(30) are arranged on a base plate. The light waveguide(40), having reflective index and being arranged at a lower part of the key buttons(20), guides the light of the light emitting elements internally by a total reflection condition. The plural reflection patters(50), formed in the light waveguide(40), reflect the light, guided into the light waveguide(40), toward the key buttons(20). The assistant layer(60), having reflective index lower than the light waveguide(40) and coated on a surface of the light waveguide(40), makes the total reflection condition regular on an overall area of the keypad.
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