Patent Application
20070064448
The present invention relates to backlight modules such as those used in liquid crystal displays (LCDs), and more particularly to a backlight module that has a tray integrally formed with a frame.
Liquid crystal displays are commonly used as display devices for compact electronic apparatuses, because they not only provide good quality images but are also very thin. As liquid crystal molecules in a liquid crystal display do not emit any light themselves, the liquid crystal molecules have to be lit by a light source so as to clearly and sharply display text and images. Therefore, liquid crystal displays usually require a backlight module.
Referring to
In assembly of the backlight module 60, the light guide plate 62 and the light emitting diodes 68 are received in the plastic frame 64, and the resulting subassembly is then received in the tray 66. The protrusions 644 of the plastic frame 64 are engaged in the notches 662 of the tray 66, whereby the plastic frame 64 and the tray 66 are locked together. However, the step of attaching the plastic frame 64 to the tray 66 is needed, which adds to the cost of manufacturing the backlight module 60. In addition, assembly tolerances apply as between the protrusions 644 and the notches 662, and these tolerances are liable to be exceeded on occasion. Moreover, the protrusions 644 are liable to be scraped when they are pressed into the respective notches 662. When this happens, loose plastic particles produced are liable to either deposit on optical surfaces of the light guide plate 62 or be dispersed in a clean room in which the backlight module 60 is assembled. That is, the light guide plate 62 or the clean room becomes contaminated.
What is needed, therefore, is a backlight module that can overcome the above-described deficiencies. What is also needed is a liquid crystal display employing such a backlight module.
In a preferred embodiment, a backlight module includes a light guide plate, and a frame assembly. The frame assembly includes a first frame and a second frame integrally formed with the first frame. The first frame accommodates the light guide plate, and has a flared protrusion. The second frame defines a flared hole therein. The protrusion of the first frame is locked in the hole.
Other aspects, advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present backlight module and liquid crystal display. In the drawings, like reference numerals designate corresponding parts throughout various views, and all the views are schematic.
Reference will now be made to the drawings to describe the preferred embodiments in detail.
The light guide plate 14 includes the light incident surface 142, a light emitting surface 144 perpendicularly connecting with the light incident surface 142, and two opposite side surfaces 146 adjacent to both the light incident surface 142 and the light emitting surface 144. Each side surface 146 has a pair of ears 148 integrally extending outward therefrom. The ears 148 are arranged near two ends of the side surface 146 respectively, and a top surface (not labeled) of each ear 148 is coplanar with the light emitting surface 144. The light guide plate 14 can for example be made from polycarbonate (PC) or polymethyl methacrylate (PMMA), and can for example be manufactured by an injection molding method.
The frame 18 includes a spacing board 182, and two symmetrically opposite first side walls 183 integrally extending from the spacing board 182. The spacing board 182 is generally frame-shaped, and protrudes perpendicularly inward from inner surfaces (not labeled) of the first side walls 183. Thus the spacing board 182 defines a rectangular space (not labeled) for accommodating the light guide plate 14. Outmost vertical faces of the spacing board 182 are either coplanar with or recessed relative to corresponding outmost vertical faces of the first side walls 183. A plurality of first protrusions 185 and a plurality of partition second protrusions 186 are formed at an inner surface of one end of the spacing board 182. The first protrusions 185 and the second protrusions 186 are disposed parallel to each other, are alternately arranged along a length of said end of the spacing board 182, and extend into the space. The second protrusions 186 are longer than the first protrusions 185. The light emitting diodes 17 can be respectively disposed in a series of spaces defined between every two adjacent second protrusions 186. That is, the light emitting diodes 17 can be arranged to abut the first protrusions 185 respectively. The spacing board 182 also defines two pairs of notches 181 positioned at two opposite inner long sides (not labeled) thereof respectively. Each notch 181 is located to correspond to a respective one of the ears 148 of the light guide plate 14. That is, the ears 148 can be received in the notches 181 respectively. The frame 18 is preferably made from white polycarbonate, plastic, or any other suitable material.
Each first side wall 183 has a generally asymmetrical U-shape, and includes a first arm 183a, a second arm 183b, and a third arm 183c. Each first arm 183a extends along a corresponding long side of the frame 18. The corresponding second arm 183b and the corresponding third arm 183c respectively extend perpendicularly inward in a same direction from two opposite ends (not labeled) of the first arm 183a. The third arm 183c is longer than the second arm 183b. The second arms 183b of the opposite first side walls 183 are generally adjacent to each other. Referring also to
Referring to
The tray 19 is integrally formed with the frame 18 to provide the frame assembly 16. The frame assembly 16 can be manufactured by an injection molding method. The bottom plate 192 of the tray 19 is located adjacent to the space defined by the spacing board 182. Each second side wall 194 of the tray 19 is located adjacent to the first arm 183a of the corresponding first side wall 183. The third side wall 195 of the tray 19 is located adjacent to the second arms 183b. The fourth side wall 196 of the tray 19 is located adjacent to the third arms 183c. Each third protrusion 184 of the frame 18 is formed in a corresponding through hole 197 of the tray 19. The outmost extremity 187 of each third protrusion 184 is flush with the outmost face of the corresponding second side wall 194. Because of the corresponding flared configurations of the third protrusions 184 and the through holes 197, the third protrusions 184 are firmly locked in the through holes 197, and the frame 18 and the tray 19 are integrally bound together as the unitary frame assembly 16.
Unlike in the prior art, because the frame assembly 16 comprises the tray 19 integrally formed with the frame 18, there is no need for a process of attaching a separate frame and a separate tray together. This makes assembly of the backlight module 12 efficient. Moreover, each third protrusion 184 is integrally formed in a corresponding through hole 197, instead of having each of protrusions pressed into a corresponding hole as in the prior art. Thus there is little or no risk of particles being scraped off from the third protrusions 184. Accordingly, the backlight module 12 is protected from contamination, and the optical performance of the backlight module 12 is unimpaired.
Referring to
Referring to
Further or alternative embodiments may include the following. The frame 18 and the tray 19 can be integrally formed by a hot pressing method, a fusion method, or a molding method. Each third protrusion 184 can have an isosceles trapezoidal configuration, a hexagonal flared configuration, a pentagonal flared configuration, or another suitable generally flared configuration.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 94130314 | Sep 2005 | TW | national |
