1. Field of the Invention
The present invention relates to touch panel technology and more particularly, to a touch panel that gives off uniform light over its entire surface.
2. Description of the Related Art
In recent years, touch panel has been intensively used in a variety of electronic products, such as PDA, intelligent mobile phone and tablet PC. A user can zoom in, zoom out or rotate the screen display, or play multimedia files simply by means of touching the display screen of the touch panel. Subject to the use of a touch panel, a touch screen mobile phone does not require a conventional mechanical numeric keypad, and therefore the size of the display screen of the touch screen mobile phone can be maximized, facilitating web browsing.
For enabling the user to operate the function keys in the sub touch zone 117 in the dark, every key pattern P must be equipped with one respective LED light source 133. This light source arrangement wastes energy and is not economic. Further, because only the key patterns P can give off light, the brightness of the entire sub touch zone 117 is not uniform.
The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a touch panel, which gives off uniform light over its entire surface.
To achieve this and other objects of the present invention, a touch panel comprises a transparent substrate, and a light guide plate arranged at the transparent substrate. The transparent substrate defines a touch surface, and a non-touch surface opposite to the touch surface. The light guide plate defines a light output surface facing toward the non-touch surface of the transparent substrate, a bottom surface opposite to the light output surface, a light incident surface connected between the light output surface and the bottom surface, and a plurality of spaced refraction zones. Subject to the arrangement of the spaced refraction zones, the touch panel produces a uniform brightness distribution across the screen.
The touch panel further comprises a flexible circuit board mounted at the bottom surface of the light guide plate, and a point light source installed in the flexible circuit board and adapted for emitting light onto the light incident surface of the light guide plate. Thus, the light emitted by the point light source can enter the light guide plate and can then be reflected or diffused by the refraction zones and finally sent out of the light output surface of the light guide plate in a uniform manner.
Further, the light guide plate of the touch panel further comprises a light-transmission plate defining a first surface corresponding to the light output surface and a second surface corresponding to the bottom surface, a first adhesive layer set between the first surface of the light guide plate and the non-touch surface of the transparent substrate, and a second adhesive layer set between the second surface of the light guide plate and the flexible circuit board. Thus, the light guide plate is positively set between the non-touch surface of the transparent substrate and the flexible circuit board.
Further, the refraction zones of the light guide plate can be arranged at one or both of the first surface and second surface of the light-transmission plate.
In one embodiment of the present invention, the light guide plate further comprises a reflective layer laminated on the second adhesive layer, and a third adhesive layer set between the reflective layer and the flexible circuit board. Thus, the reflective layer reflects the light coming out of the second surface of the light-transmission plate backwardly onto the inside of the light-transmission plate, raising the light utilization rate.
In the preferred embodiment of the present invention, the light guide plate further comprises a diffusion layer laminated on the first adhesive layer, and a fourth adhesive layer set between the diffusion layer and the non-touch surface of the transparent substrate. Thus, the diffusion layer diffuses the light coming out of the light output surface of the light guide plate, enhancing uniform distribution of light and softening the light.
Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.
Referring to
The transparent substrate 30 can be made of, but not limited to, glass, polycarbonate (PC), polymethyl methacrylate (PMMA), or cycloolefin copolymer (COC). The transparent substrate 30 comprises a touch surface 31, and a non-touch surface 33 opposite to the touch surface 31. The touch surface 31 is divided into a main touch zone 35 and a sub touch zone 37 at the border area of the main touch zone 35. Further, the non-touch surface 33 has a plurality of key patterns P printed or coated thereon at selected locations corresponding to the sub touch zone 37.
The flexible circuit board 40 has a circuit layout arranged thereon. The point light source 50 can be, for example, but not limited to, a LED (light-emitting diode). The flexible circuit board 40 is electrically coupled with the point light source (LED) 50, providing the point light source (LED) 50 with the necessary working voltage.
The light guide plate 60, as shown in
Thus, the light emitted by the point light source 50 will fall upon the light incident surface 605 into the inside of the light guide plate 60, and will then be reflected onto or dispersed over the entire light output surface 601 of the light guide plate 60 by the dots of the refraction zones 607, uniformly brightening the entire surface of the sub touch zone 37 of the transparent substrate 30.
Actually, the light guide plate 60 used in the touch panel 20 can be variously embodied.
Further, it is to be understood that the aforesaid reflective layer 64 or diffusion layer 66 is optional. Both the reflective layer 64 and the diffusion layer 66 can exist concomitantly or individually. Further, during fabrication, the configuration of the refraction zones 607 of the light guide plate 60 is not limited to the aforesaid dot pattern. For example, the refraction zones 607 of the light guide plate 60 can be configured to provide a stripe pattern (see
In conclusion, the touch panel of the present invention has built therein a light guide plate having spaced refraction zones, therefore, the invention simply needs to use one single LED to produce a uniform brightness distribution across the screen. When compared with conventional touch panels, the invention saves energy consumption and enables the touch panel to give off uniform light over the entire surface of its sub touch zone. Further, subject to the arrangement of a reflective layer or diffusion layer, the invention greatly raises the luminous efficiency of the touch panel.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
Number | Date | Country | Kind |
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100125316 | Jul 2011 | TW | national |