1. Field of the Invention
The present invention relates to a keycap, and in particular to a light-guiding method and a light-guiding assembly of a backlight source within the keycap.
2. Description of Prior Art
Back light source can be widely used in a liquid crystal display, a signboard or an advertisement board. In addition, it can be also applied to electronic products, such as mobile phone or personal digital assistant. Since the back light module is mounted within the keycap, the user can still smoothly operate the keycaps even in the night or without the illumination of a light source.
The conventional keycap is provided with a light-guiding plate in the interior of the key pad assembly, and the periphery or the bottom of the light-guiding plate is provided with a light-emitting diode. When the electronic product is in use, the light-emitting diode is lighted up, and the light is introduced into the light-guiding plate. At this time, with the light-guiding plate, the light is directed to the keycap above the light-guiding plate, so that the surface of the keycap has a light-transmitting effect. In this way, the user can clearly see the character, numeral or symbol on the surface of each keycap.
Recently, with the development of multi-color light-emitting diodes, they are also widely used in the keycaps of electronic products. The multi-color light-emitting diode generates the lights with various colors under the control of the circuit of the electronic product to, so that the surface of the keycap or some keycap groups can represent a colored back light effect with different colors. Since there is only one layer of light-guiding plate, if several multi-color light-emitting diodes are lighted up at the same time, and the lights with various colors are simultaneously introduced into the light-guiding plate, these lights may be mutually interfered with one another or mixed easily. As a result, the light displayed on the surface of the keycap is not the originally preset light. Therefore, in order to solve the mutual interference or mixing of the lights, adhesion of black patches or coating of inks is applied to the light-guiding plate so as to shield the light. After several multi-color lights are introduced into the light-guiding plate, the surface of the keycap or some keycap groups may represent a backlight effect with various colors and do not generate the interference or mixing of the lights. However, if the adhesion or coating process is not perfectly performed, such light-shielding measure may cause the leakage of light and in turn the waste of time and process in manufacturing the light-guiding plate.