Patent Application
20070296341
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Still referring to
In addition, the thickness of the blue light fluorescent layer 230 disposed on the second surface 210b of the second substrate 214 may be between 2 μm and 10 μm, and the discharge gas 240 is xenon (Xe), argon (Ar), helium (He), deuterium (D2) or other proper inert gases for instance.
Furthermore, the cold cathode fluorescent flat lamp 200 may further comprises a dielectric layer 260 dispose on the first surface 210a for covering the first electrodes 220, such that the first electrodes 220 and discharge gas 240 are electrically isolated and the bombardments on the first electrodes 220 by the ions produced during the plasma formation of discharge gas 240 can be blocked. In another embodiment of the invention, as shown in
It's worthy to note that, for the purpose of to emitting mixed lights, the cold cathode fluorescent flat lamp 200 may further comprise fluorescent layers capable of emitting lights of other colors. In the present embodiment, the cold cathode fluorescent flat lamp 200 may comprise a light-mixing fluorescent layer 250 disposed on the first surface 210a of the first substrate 212 and located between the first electrodes. Further, the light-mixing fluorescent layer 250 is suitable for emitting a mixing light of red and green lights and its thickness may be between 10 μm and 200 μm.
The cold cathode fluorescent flat lamp 200 is operated by applying a driving voltage on the first electrodes 220 to ionize the discharge gas 240 into plasma state. Following that, the resulting ultraviolet rays excited by the plasma are provided to light the blue light fluorescent layer 230 and light-mixing fluorescent layer 250 such that blue lights emitted by the blue light fluorescent layer 230 and mixing lights of green and red lights emitted by the light-mixing fluorescent layer 250 are mixed together and form the white light accordingly.
During the operating process described above, since the first electrodes 220 are disposed on the first substrate 212, the ions ionized from the discharge gas 240 in the process of forming plasma tend to be closer to the first substrate 212. At this time, the blue light fluorescent layer 230 is disposed on the second substrate 214 and is far away from those ions. Therefore, based on the descriptions above, the blue light fluorescent layer 230 may suffer from fewer ion bombardments compared with the light-mixing fluorescent layer 250, so the intensity of the blue light emitted by the blue light fluorescent layer 230 decays slowly. In this way, after long-term usage the cold cathode fluorescent flat lamp 200 can still stably emit uniform white light and no deviation of the Color Chromaticity occurs.
Additionally, to effectively resist the ion bombardments on the blue light fluorescent layer 230 during the plasma formation of the discharge gas 240, the cold cathode fluorescent flat lamp 200 of the present embodiment can further comprise a protection layer 270 disposed on the blue light fluorescent layer 230. And the material of the protection layer 270 includes Magnesia (MgO) or magnesium fluoride (MgF2). Because the protection layer 270 can prevent the ion bombardments, formed during the plasma formation of the discharge gas 240, on the blue light fluorescent layer 230. Thus, the decaying rate of the intensity of blue lights emitted by the blue light fluorescent layer 230 can be effectively lowered.
To sum up, for the cold cathode fluorescent flat lamp provided by the present invention, since the first electrodes are disposed on the first substrate and the blue light fluorescent layer is dispose on the second substrate, the blue light fluorescent layer can suffer from fewer ion bombardments and the intensity of blue light emitted by the blue light fluorescent layer decays slowly. Thus, the blue light fluorescent layer can stably emit blue lights and life of the cold cathode fluorescent flat lamp is increased thereby.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.
