| 摘要 |
Light-emitting diodes are positioned directly under each key of a multi-key flexible pad of a keypad assembly. Each of the light-emitting diodes is disposed within a cavity formed in the lower surface of a respective key whereby all of the light emitted by the diode is transmitted directly into the key. In one embodiment, the light-emitting diodes are mounted on a flexible film disposed between the flexible pad containing the keys and a flexible sheet having a plurality of raised domes. In a second embodiment, the light emitting diodes are mounted on the upper surface of a printed circuit board. The keypad assembly addresses the problem of low light transmission efficiency through light guides, or the use of individual optic fibers to illuminate each of the keys. Furthermore, the keypad assembly, by the elimination of light transmitting structures within the keypad assembly, enables the design of thin-section telecommunication instruments. Each of the contacts on the flexible film is arranged for connection with a predetermined electrical contact disposed on the printed circuit board. |
