Patent Application
20070183134
The present invention relates to displaying of images.
Display devices that incorporate liquid crystal displays (LCDs) are used in a variety of applications. By way of example, such display devices are used in laptop computers, cellular phones and flat screen televisions. In order to display images using such a display device, a source of light typically is provided. A source of light that is arranged behind a display portion of a display device is typically known as a backlight module.
An example of a typical implementation of a display device is depicted schematically in
The backlight module 14 (a schematic plan view of which is depicted in
The backlight module 14 includes an upper substrate 32 and a lower substrate 34 that are spaced from each other. Channels 36A-36F, which are defined by corresponding barrier walls 38A-38G, are parallel to each other and extend linearly across the backlight module. In particular, the channels extend between electrodes 40 and 42. The channels are covered with a fluorescent material that emits visible light in response to exposure to ultra-violet light. In this regard, the channels also are filled with discharging gas that emits ultra-violet light in response to excitation by electrons travelling between the electrodes (not shown in
In an effort to improve uniformity of light emitted by a backlight module, several approaches have been used. By way of example, wider channels can be used. However, wider channels result in lower efficiency. Unfortunately, narrower channels can solve the efficiency problems, but provide lower uniformity.
In this regard, systems for displaying images are provided. According to one embodiment of the present invention, it is provided a system which comprises a backlight module comprising an upper substrate, a lower substrate, a channel, a discharging gas, a fluorescent material, a cathode and an anode. The channel exhibits a series of waves arranged along a length thereof. The discharging gas and the fluorescent material are located within the channel. The cathode and the anode are spaced from each other along the length of the channel. The series of waves forms an increased effective length of the channel through which electrons travel between the cathode and the anode, and within which the electrons excite the discharging gas to generate ultra-violet light. Responsive to the ultra-violet light, the fluorescent material emits visible light.
According to another embodiment of the present invention, it is provided a system which comprises a lower substrate, an upper substrate, a channel, a discharging gas, a fluorescent material, a cathode and an anode. The upper substrate overlies and is spaced from the lower substrate. The channel is located between the lower substrate and the upper substrate. The discharging gas and the fluorescent material are located within the channel. The cathode is located adjacent a first end of the channel and the anode is located adjacent a second end of the channel. The cathode is operative to provide electrons to excite the discharging gas, thereby causing the discharging gas to generate ultra-violet light. Responsive to the ultra-violet light, the fluorescent material emits visible light. Additionally, the first barrier wall undulates along a length thereof between the first end and the second end of the channel.
According to still another embodiment of the present invention, it is provided a system which comprises a display device having a display module and a backlight module. The display module is operative to receive light emitted from the backlight module. The backlight module comprises a channel, a discharging gas and a fluorescent material. The channel has sides and exhibits a serpentine shape, with the sides of the channel undulating along a length thereof such that waves of the undulating channel are superimposed on the serpentine shape. The discharging gas and the fluorescent material are located within the channel. The channel restricts electrons to travel along a length thereof, with the electrons being operative to excite the discharging gas to generate ultra-violet light such that the fluorescent material emits visible light that emits from the backlight module.
Other systems, methods, features and/or advantages of the present invention will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features and/or advantages be included within this description and be protected by the accompanying claims.
The components in the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding parts throughout the several views.
As will be described in detail here, systems for displaying images are provided. In some embodiments, uniformity of light provided by a backlight module can be improved as compared to conventional backlight modules. This can be accomplished by forming channels of the backlight module with the channel exhibiting undulations along a length thereof. Since these channels incorporate non-linear features, variations in lighting intensity due to the barrier walls that define the channels may be imperceptible to a viewer of a display device that is provided with light by such a backlight module.
Additionally, some embodiments may provide relatively high efficiency light output and uniformity without requiring an increase in a number of channels of the backlight module. This can be accomplished by increasing the effective length of the channels through which electrons travel. That is, by providing undulating channels, the effective length of each of the channels is increased, thereby improving illumination efficiency of the channels. Thus, since the number of channels is not increased, the total current requirements for the backlight module can be maintained at a relatively low level, while providing a high efficiency light output.
In this regard, an embodiment of a backlight module incorporating undulating channels is depicted in the schematic plan view of
The channels are covered with fluorescent material that emits visible light through the upper substrate 104 in response to exposure to ultra-violet light. In this regard, the channels also are filled with discharging gas that emits ultra-violet light in response to excitation by electrons travelling between the cathode 130 and the anode 134.
In this embodiment, each of the barrier walls exhibits a similar shape such that the walls are substantially equidistant from each other along their lengths. Additionally, each of the barrier walls exhibits a series of waves that extends generally the entire length of the corresponding barrier wall. Note that although the waves depicted in the embodiment of
In operation, the backlight module emits light that is directed towards the display module. The display module uses the LCD panel to modulate the light for displaying images.
Notably, the display device does not incorporate a diffusion plate, prism sheet or other such provisions for diffusing light provided by the backlight module. This is because the backlight module 100 provides light of adequate uniformity such that provisions for diffusing light may be omitted in some embodiments. Clearly, this can result in a reduction in component cost for a display device incorporating such a backlight module.
Various alternative embodiments of backlight modules are depicted in the schematic plan views of
In particular, backlight module 190 of
Another embodiment of a backlight module is depicted in
It should be emphasized that many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be protected by the following claims.
