BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a schematic cross-sectional view showing a conventional direct type backlight module.
FIG. 1B is a perspective view showing the deformation of the optical film of a conventional direct type backlight module.
FIG. 2 is a schematic cross-sectional view showing a direct type backlight module according to the first embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view showing a direct type backlight module according to the second embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view showing a direct type backlight module according to the third embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
First Embodiment
FIG. 2 is a cross sectional view showing a direct type backlight module according to the first embodiment of the present invention. Please referring to FIG. 2, the direct type backlight module 200 of the present embodiment includes a frame 210, a plurality of light sources 220, an optical plate 230 and an upper frame 240, wherein the frame 210 includes a bottom frame 212 and a side frame 214 extending upward from the edge of the bottom frame 212. The light sources 220 are disposed on the bottom frame 212, and the optical plate 230 is disposed on the side frame 214 above the light sources 220. The frame 210 and the upper frame 240 are assembled, wherein the optical plate 230 is located between the upper frame 240 and the frame 210. It should be noted that the upper frame has at least one protrusion 240a located above the optical plate 230 and protruding to the optical plate 230.
More specifically, the distance W between the top surface 242a of the protrusion 240a and the optical plate 230 is, for example, between 0 to 0.1 mm. In addition, the material of the protrusion 240a can be metal or plastic and the shape of the protrusion 240a could be cylinder or strip. The optical plate 230 is, for example, a diffusion plate and the light sources 220 could be point light sources or linear light sources. The linear light sources are, for example, cold cathode fluorescent lamp (CCFL), and the point light sources may be light emitting diode (LED), organic light emitting diode (OLED), or other similar light sources. In the present embodiment, the side frame 214 has a recess 214a and the optical plate 230 is disposed on the recess 214a. However, the side frame 214 in the present invention is not limited to have the recess 214a.
The deformation of the optical plate 230 can be reduced because the protrusion 240a is restraining the warping and deformation of the optical plate 230 at a high temperature environment, and thus the display mura phenomenon can be reduced.
Second Embodiment
FIG. 3 is a cross sectional view showing a direct type backlight module according to the second embodiment of the present invention. Referring to FIG. 3, the present embodiment is similar to the first embodiment, but the difference is that the optical plate 230 has at lease one concave 230a to contain the protrusion 240a. Moreover, the distance W between the top surface 242a of the protrusion 240a and the concave 230a is, for example, between 0 to 0.1 mm. Therefore, the shifting of the optical plate 230 is restricted by the protrusion 240a and thus the display mura phenomenon can be reduced. In addition, a predetermined gap is maintained between the upper frame 240 and an optical film 250.
In the present embodiment, the direct type backlight module 200 further includes at least one optical film 250 disposed on the optical plate 230, and the protrusion 240a is located on the outside of the optical film 250. Additionally, the optical film 250 is, for example, a lower diffusion film, a light-collecting film, an upper diffusion film or other optical film.
Third Embodiment
FIG. 4 is a cross sectional view showing a direct type backlight module according to the third embodiment of the present invention. Referring to FIG. 4, this embodiment is similar to the second embodiment, the difference is that the optical plate 310 of the direct type backlight module 300 of the present embodiment has at least one protrusion 310a located at the edge thereof and the upper frame 320 covers the protrusion 310a. Wherein, the shape of the protrusion 310a is, for example, cylinder or strip. In the present embodiment, the upper frame 320 has at least one concave 320a to contain the protrusion 310a. However, the upper frame 320 of the present embodiment is not limited to include a concave 320a, and the upper frame 320 without a concave 320a (as shown in the FIG. 2) can be applied to the present embodiment as well.
The distance W between the top surface 312a of the protrusion 310a and the concave 320a is, for example, between 0 to 0.1 mm. Therefore, the shifting of the optical plate 310 is restricted by the concave 320a and thus the display mura phenomenon can be reduced.
The present invention has been disclosed above in the embodiments, but is not limited to those. It is known to persons skilled in the art that some modifications and innovations may be made without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be defined by the following claims.
Patent Application
20080089061
