Patent Application
20060104087
1. Field of the Invention
The invention relates generally to direct type backlight modules and, more particularly, to a direct type backlight module with a high heat dissipating efficiency.
2. Description of the Related Art
Backlight modules are used in liquid crystal display devices for converting linear light sources such as cold cathode ray tubes or point light sources such as light emitting diodes into area light sources having high uniformity and brightness. Backlight modules generally include edge lighting backlight modules and direct type backlight modules. A typical edge light backlight module generally need requires a light guide plate, while a typical direct type backlight module does not need not a light guide plate, and thereby having has a relatively simple structure.
Referring to
In use, heat produced by the lamps 14 can be transferred to the heat dissipating plate 59 via air convection between the first chamber 60 and the second chamber 70. Thus, the heat can be dissipated into the external environment via the fin type structure 54a. However, the means of air convection has a relatively small thermal conductivity coefficient, and, as such, a heat dissipating velocity thereof is slow. After a long time working, the heat accumulated in the backlight module 50 can't be transferred to the heat dissipating plate 59 in time, and, accordingly, the heat can't be dissipated into the external environment effectively.
What is needed, therefore, is a direct type backlight module having high heat dissipating efficiency.
In one embodiment, a direct type backlight module includes a housing, a reflection plate, a diffusion plate and a plurality of lamps. The housing includes a window portion, a base portion and a side portion located between edges of the window portion and the base portion. The reflection plate is positioned in the housing, supported by the side portion, thereby dividing the housing into a first room and a second room. The diffusion plate is located at the window portion of the housing. The lamps are positioned in the first room, between the diffusion plate and the reflection plate. A plurality of openings is defined in the side portion, and each opening communicates with the first room.
Furthermore, a film is coated on a surface of the diffusion plate that faces the lamps. The film is advantageously formed by alternately depositing silicon dioxide and titanium trioxide via ion-beam assisted deposition and/or plasma sputtering deposition.
Compared with a conventional direct type backlight module, the inventive direct type backlight module has the following advantages. Firstly, forced cooling air can be introduced into the first room via the openings to dissipate accumulated heat therefrom and into the external environment effectively. This forced air flow ensures that the inventive direct type backlight module has a high heat dissipating efficiency. Secondly, as only visible light can pass through the film on the diffusion plate, heat produced by the lamps is restricted in the first room and can not pass through the film in the form of infrared light waves. Thus, a liquid crystal display device incorporating the inventive direct type backlight module can have good imaging quality. Furthermore, since the heat produced by the lamps can be effectively dissipated into the external environment by the forced cooling air introduced into the first room, the direct type backlight module can be advantageously applied in liquid crystal display devices.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings.
The above-mentioned and other features and advantages of the invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Reference will now be made to the drawings to describe embodiments of the present invention in detail.
Referring to
In the embodiment, the reflection plate 130 is rippled and/or undulated, thereby increasing resistance of the forced cooling air 172 flowing therealong. This increased airflow resistance results in refluence (i.e., back flow or reflux) of the forced cooling air 172, thereby enhancing the utilization ratio of the forced cooling air 172 in the first room 150. Thus, a cooling efficiency of the forced cooling air 172 is enhanced.
Furthermore, a film 180 is coated on a surface of the diffusion plate 120 and faces the lamps 140. The film 180 is advantageously formed by alternately depositing silicon dioxide and titanium trioxide via ion-beam assisted deposition and/or plasma sputtering deposition. A thickness of every silicon dioxide layer is in the approximate range of from 73 to 185 nanometers, and a thickness of every titanium trioxide layer is about in the range of from 80 to 115 nanometers. Only visible light having a wavelength generally in the range from 370 to 700 nanometers can pass through the film 180. Therefore, heat produced by the lamps 140 is restricted in the first room 150, the heat being incapable of passing through the film 180 in the form of infrared light waves. Thus, a liquid crystal display device incorporating the direct type backlight module 100 can have good imaging quality. Furthermore, the heat produced by the lamps 140 can be readily dissipated into the external environment by the forced cooling air 172. Therefore, the direct type backlight module 100 can be advantageously applied in liquid crystal display devices.
Finally, it is to be understood that the above-described embodiments are intended to illustrate rather than limit the invention. Variations may be made to the embodiments without departing from the spirit of the invention as claimed. The above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 93134600 | Nov 2004 | TW | national |
