This application claims the priority benefit of Taiwan application serial no. 93104041, filed on Feb. 19, 2004.
1. Field of the Invention
The present invention generally relates to a cold cathode fluorescent flat lamp (CCFFL). More particularly, the present invention relates to a cold cathode fluorescent flat lamp having high brightness uniformity.
2. Description of Related Art
In recently years, portable electronic devices such as mobile phone, digital camera, digital video camera, notebook or desktop computer or personal computer have been developed drastically with the development of semiconductor processes and the display components. It is noted that, for all the electronic devices described above, the display device is essential and important for data input/output between the user and the device. Recently, a variety of display devices is constructed by the liquid crystal display (LCD) panel. Since the LCD panel is not self illuminant, a backlight module is required, which is typically disposed under the LCD panel as a light source.
The conventional backlight module generally includes a lamp tube, a reflection holder and a light guide plate (LGP). The light guide plate can transfer the line light source emitted by the lamp tube into surface light source. Generally, since the lamp tube is mounted on the edge of the light guide plate, the uniformity of the surface light source emitted by the light guide plate is worse. Therefore, a plurality of optical films, such as, diffuse films or brightness enhancement films is disposed above the light exit plane of the light guide plate. Therefore, the cost of the backlight module is expensive as the light guide plate and optical film are expensive. Moreover, the lamp tube, the reflector holder and the light guide plate are individual components and must be mounted by a glue trim. Therefore, the construction of the conventional backlight module is complex and high-cost.
In recent years, the cold cathode fluorescent flat lamp (CCFFL) having high luminous efficiency and uniformity is developed and provided as a surface light source, especially for a large surface area. In addition, the cold cathode fluorescent flat lamp (CCFFL) has been broadly applied as the backlight of the liquid crystal display panel and in many other applications.
The cold cathode fluorescent flat lamp (CCFFL) is a plasma light emitting component, and the principle of light emitting thereof is not exactly known, however, it is most likely as described below. First, electrons are emitted by the cathode, and thereby the inert gas in the cavity is impacted by the emitted electrons between the cathode and the anode. As a result, the inert gas is ionized into plasma and is subjected to an excited state. Next, when the atomic gas of the plasma returns to the ground state from the excited state,certain amount of energy is lost in the plasma in the form of ultraviolet light. The emitted ultraviolet light will excite the fluorescence material disposed on the cavity wall of the light tube to generate visible light.
In the discharge process described above, the light emitted by the cold cathode fluorescent flat lamp (CCFFL) is generally constructed as a line light source. When the cold cathode fluorescent flat lamp (CCFFL) is provided as a surface light source, the light on the plane is not uniform. Therefore, a local discharge process is provided by, for example,providing a plurality of protrusions on the electrodes, and thus light is emitted by point discharge at the protrusions. Hence, a cold cathode fluorescent flat lamp (CCFFL) with a larger surface area may be constructed by a plurality of local plane lamps.
However, in the local discharge process, the light intensity at the point of discharge of the cold cathode fluorescent flat lamp (CCFFL) is larger than other areas, and therefore, an interlaced brightness distribution is formed in the surface of the light source. Therefore, a better brightness uniformity of the (influence)? cold cathode fluorescent flat lamp (CCFFL) is highly desirable.
Accordingly, the present invention is directed to a cold cathode fluorescent flat lamp for increasing the light intensity emitted from the region without point discharge to increase the brightness uniformity of the cold cathode fluorescent flat lamp.
In addition, the present invention is also directed to a cold cathode fluorescent flat lamp (CCFFL) for reducing the light intensity emitted by the region of point discharge to increase the brightness uniformity of the cold cathode fluorescent flat lamp.
According to an embodiment of the present invention, a cold cathode fluorescent flat lamp (CCFFL) comprising, for example but not limited to, a cavity, discharge gas, a plurality of electrodes, fluorescence layer and first light control layer is provided. The cavity has a light exit plane. The discharge gas is filled in the cavity, and the electrodes may be, for example but not limited to, disposed inside the cavity or outside the cavity. The fluorescence layer is disposed on the inner wall of the cavity. The first light control layer is disposed over the fluorescence layer corresponding to the light exit plane of the cavity.
In one embodiment of the present invention, the cavity comprises, for example but not limited to, a first substrate, a second substrate and a side bar. The second substrate is disposed over the first substrate, and the side bar is disposed between the first and the second substrates and connected to the edge thereof.
In one embodiment of the present invention, the discharge gas comprises, for example but not limited to, an inert gas such as xenon (Xe), argon (Ar) or neon (Ne).
In one embodiment of the present invention, the electrodes of the cavity comprises, for example but not limited to, a plurality of protrusions. In another embodiment of the invention, the electrodes, for example but not limited to, divide the cavity into at least one sub-cavity, and the sub-cavity is divided by the protrusions of the electrodes into a plurality of first light emitting areas and second light emitting areas. The second light emitting areas are, for example but not limited to, disposed between the first light emitting areas. The first light control layers are disposed over the fluorescence layer corresponding to the first light emitting areas.
In one embodiment of the present invention, the first light control layer may be comprised of, for example but not limited to, a fluorescence material. In another embodiment of the invention, the material of the first light control layer is, for example but not limited to, same as the material of the fluorescence layer.
In one embodiment of the present invention, the first light control layer comprises, for example but not limited to, a single patterned film layer or multi-layer stacked patterned film layer.
In one embodiment of the present invention, the cold cathode fluorescent flat lamp (CCFFL) further comprises a second light control layer disposed over the fluorescence layer corresponding to the first light control layer. In one embodiment of the present invention, the second light control layer is disposed over the fluorescence layer corresponding to the second light emitting areas.
In one embodiment of the present invention, the second light control layer comprises, for example but not limited to, a fluorescence material. In another embodiment of the invention, the material of the second light control layer is, for example but not limited to, same as the material of the fluorescence layer.
In one embodiment of the present invention, the second light control layer comprises, for example but not limited to, a single patterned film layer or multi-layer stacked patterned film layer.
In addition, the present invention provides a cold cathode fluorescent flat lamp comprising a cavity, discharge gas, a plurality of electrode, fluorescence layer and second light control layer. The cavity has a light exit plane opposite to the bottom surface. The discharge gas is filled in the cavity, and the electrodes can be disposed inside the cavity or outside the cavity. The fluorescence layer is disposed on the inner wall of the cavity. The second light control layer is disposed over the fluorescence layer corresponding to the bottom surface of the cavity.
In one embodiment of the present invention, the cavity comprises a first substrate, a second substrate and a side bar. The second substrate is disposed over the first substrate, and the side bar is disposed between the first and the second substrate and connected to the edge thereof.
In one embodiment of the present invention, the discharge gas comprises, for example but not limited to, an inert gas such as xenon (Xe), argon (Ar) or neon (Ne).
In one embodiment of the present invention, the electrodes of the cavity comprise, for example but not limited to, a plurality of protrusions. In another embodiment of the invention, the cavity is divided by the electrodes into, for example but not limited to, at least one sub-cavity, and the sub-cavity is divided by the protrusions of the electrodes into a plurality of first light emitting areas and second light emitting areas. The second light emitting areas are, for example but not limited to, disposed between the first light emitting areas. The second light control layer is disposed over the fluorescence layer corresponding to the second light emitting areas.
In one embodiment of the present invention, the second light control layer comprises, for example but not limited to, a fluorescence material. In another embodiment of the invention, the material of the second light control layer is, for example but not limited to, same as the material of the fluorescence layer.
In one embodiment of the present invention, the second light control layer comprises, for example but not limited to, a single patterned film layer or a multi-layer stacked patterned film layer.
Accordingly, in the present invention,the first or the second light control layers disposed on the fluorescence layer over the cavity wall of the cold cathode fluorescent flat lamp can increase the brightness uniformity of the light exit from the whole cold cathode fluorescent flat lamp.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
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 following drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
The present invention is related to a design of a variety of patterns and a variety of fluorescence material with different thickness in the cold cathode fluorescent flat lamp (CCFFL) for increasing the brightness uniformity of the light emitted from the cold cathode fluorescent flat lamp. Hereinafter,some embodiments of the disposing method of the pattern and fluorescence material of the cold cathode fluorescent flat lamp will be described. However, the embodiment is only provided for the description of the invention and cannot be used to limit the scope of the present invention.
Next, referring to
It is noted that, the electrodes 106 may comprise, for example but not limited to, a plurality of protrusions 120, and thus every sub-cavity 128 is divided into, for example but not limited to, a first light emitting area 122 and a second light emitting area 124. Since the current between each pair of opposite protrusions 120 is larger, the intensity of the ultraviolet light emitted from the first light emitting area 122 is larger than that emitted from the second light emitting area 124. It is noted that, the light intensity emitted by the cold cathode fluorescent flat lamp (CCFFL) 100 is dependent on the intensity of the ultraviolet light described above, and moreover, dependent on the amount of the fluorescence substance irradiated by the ultraviolet light in a time period.
Next, referring to
It is noted that, in the embodiment described above, only one first light control layer 110 is provided. However, in the present invention, more than one light control layers may also be utilized to achieve the purpose of the present invention. In another embodiment of the present invention in, the first light control layer may be a multi-layer stacked patterned film layers,such as the first light control layer 210 shown in
It is noted that, in the embodiment described above, the light intensity of light emitted from the first light emitting area 122 may be decreased in order to increase the uniformity of the whole brightness of the surface light source. However, in another embodiment of the invention, the light intensity of light emitted from the second light emitting area 124 may be increased in order to increase the uniformity of the whole brightness of the surface light source. Hereinafter,the embodiment will be described.
Referring to
In one embodiment of the invention, the second light control layer 126 comprises, for example but not limited to, a patterned film layer 126a and a patterned film layer 126b. The patterned film layer 126a, for example but not limited to, covers the fluorescence layer 108 of the second light emitting area 124 correspondingly. The patterned film layer 126b is, for example but not limited to, disposed over the dot shape or grating shape film layer of the patterned film layer 126a. The patterned film layer 126a and the patterned film layer 126b may effectively increase the area of the fluorescence material irradiated by the ultraviolet light at any given time. In other words, the fluorescence material in the second light emitting area 124 irradiated by the ultraviolet light is increased, and thus the light intensity of light emitted by the second light emitting area 124 is increased and is approximate to the light intensity of light emitted by the first light emitting area 122.
In the embodiments described above, the present invention is not limited to the second light control layer. In another embodiment of the present invention, the second light control layer may be a single patterned film layer, or a multi-layer stacked patterned film layer. Referring to
Moreover, in another embodiment of the present invention, the cold cathode fluorescent flat lamp (CCFFL) of the invention may comprise both the first light control layer and second light control layer. Accordingly, the whole brightness uniformity of the cold cathode fluorescent flat lamp (CCFFL) may be further improved.
Accordingly, in the present invention,one or multilayer stacked light control layer is disposed over the fluorescence layer inside the cavity wall of the cold cathode fluorescent flat lamp (CCFFL). Therefore, the brightness uniformity of the whole cold cathode fluorescent flat lamp (CCFFL) is enhanced. Since the present invention can solve the problem of the interlaced brightness of the conventional local discharge plane lamp, the present invention may be provided for manufacturing a cold cathode fluorescent flat lamp (CCFFL) having high brightness uniformity and a large surface area.
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, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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93104041 | Feb 2004 | TW | national |