Patent Application
20090262518
1. Field of the Invention
The present invention relates to light guiding mechanisms and, particularly to a light guiding mechanism used in portable electronic devices.
2. Description of Related Art
Portable electronic devices usually include keypads for inputting information. When operating such portable electronic devices in a dark room, keys of the keypads need to be illuminated to be seen and operated by users. Each key can be illuminated by a light source corresponding to the key. However, this type of keypad is expensive since a many light sources are required.
A typical way to reduce the number of light sources is to use a light guiding member in the form of a transparent plate. A typical light guiding member includes an array of apertures. As each key is arranged to align with the corresponding aperture, and the keys are illuminated by the light guided by the light guiding member. However, bright areas of the light guiding member may appear where the light sources are disposed adjacent to the light guiding member. Thus, there is decreased illumination uniformity of the light guide plate, which increases the difficulty of producing a desirable uniform illumination for the keypad.
Therefore, there is room for improvement within the art.
Many aspects of a light guiding mechanism can be better understood with reference to the following drawings. These drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present light guiding mechanism. Moreover, in the drawings like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.
Embodiments will now be described in detail below and with reference to the drawings. The light guiding mechanism can be applied to an electronic device, for example, a mobile phone. Therefore, the light guiding mechanism is shown in the abstract, rather than associated with any particular electronic device.
The circuit board 10 is generally rectangular and includes a surface 12 facing the light guiding mechanism 20. The circuit board 10 has a plurality of light sources 14 on its surface 12. The light sources 14 may be light emitting diodes (LEDs). When the light sources 14 are placed within the light guiding mechanism 20, light generated by the light sources 14 can be guided to illuminate keys of a keypad assembly (not shown).
The light guiding mechanism 20 includes a light guiding plate 22 and a plurality of shielding plates 24.
The light guiding plate 22 defines a plurality of first holes 26 and a plurality of cutouts 28 therethrough. The first holes 26 should correspond to and accommodate the keys of the keypad assembly. The light sources holes 28 should correspond to and accommodate the light sources 14. The light guiding plate 22 can be made of one or more materials selected from a group consisting of polyvinyl chloride (PVC), polycarbonate, polystyrene, and any other thermoplastic resins.
Each shielding plate 24 has substantially the same shape as of its corresponding second holes 28 but have a larger size than its corresponding second holes 28. The plurality of shielding plates 24 is disposed (e.g., bolted) on the light guiding plate 22 and configured for shielding the second holes 28. The shielding plates 24 can be made of various kinds of materials according to actual requirements. The shielding plate 24 can be made of an opaque material with a black color (e.g., the compound of resin and carbon) to prevent light penetration through the second holes 28. Conversely, the shielding plate 24 can be made of a semi-transparent material (e.g., a compound of resin and white metal) to allow light penetration through the second holes 28.
as the shielding plate 24 can be made from any material with any color, light passing through the second holes 28 can correspond to the color of the shielding plate 24.
An advantage of the exemplary embodiment is as follows. Brightness areas of the light guiding plate 22 usually appears where the light sources 14 are disposed adjacent to the light guiding plate 22. The plurality of shielding plates 24 are disposed on the light guiding plate 22 shielding the light sources 14 to eliminate the bright areas of the light guiding plate 22. Therefore, illumination uniformity of the light guide plate 22 is improved.
Another advantage of the exemplary embodiment is as follows. Light guided by the light guiding mechanism 20 can be provided with a certain color, which can be achieved by manufacturing the shielding plate 22 from a material having the desired color.
It is to be understood, however, that even through numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200810301154.9 | Apr 2008 | CN | national |
