US 7360940 B2
An exemplary backlight module (5) includes a light guide plate (54) having a light incident surface (546), and a circuit board (62) disposed adjacent to the light incident surface. A pair of protrusions (544) of the light guide plate engages in a pair of fixing holes (524) of the circuit board, thereby fixing the circuit board and the light guide plate together. The backlight module may further include one or more optical films. In such case, the above-described fixing means may further include a plurality of side-blocks or a plurality of corner-blocks integrally formed on a light emitting surface of the light guide plate. The side-blocks or corner-blocks enable the optical films to be tightly held on the light guide plate without gaps therebetween.
1. A backlight module, comprising:
a light guide plate having a light incident surface, a light emitting surface adjoining the light incident surface;
a circuit board disposed adjacent to the light incident surface; and
a fixing means attaching the circuit board and the light guide plate together, which comprises two ears formed with the light guide plate, and each ear comprises a protrusion;
wherein the circuit board comprises two fixing holes corresponding to the protrusions.
2. The backlight module as claimed in
3. The backlight module as claimed in
4. The backlight module as claimed in 3, further comprising an optical film defining two notches corresponding to the side-blocks.
5. The backlight module as claimed in
6. The backlight module as claimed in
7. The backlight module as claimed in
8. The backlight module as claimed in
9. The backlight module as claimed in
10. The backlight module as claimed in
The present invention relates to backlight modules, and especially to a backlight module for liquid crystal display (LCD) devices.
Liquid crystal displays are commonly used as display devices for compact electronic apparatuses, because they not only provide good quality images with little power but also are very thin. The liquid crystals in a liquid crystal display do not emit any light themselves. The liquid crystals have to be lit by a light source so as to clearly and sharply display text and images. Thus, a backlight module for an LCD is generally needed.
The FPC 12 is arranged adjacent to the light incident surface 141 of the light guide plate 14, and the diffusing film 15 and the prism films 16 are arranged on the light emitting surface 142 of the light guide plate 14. It is difficult to obtain an exact fit when assembling the FPC 12, the diffusing film 15, and the prism films 16 together. Further, even if a compact assembly is attained, the assembly may loosen and become unstable when the backlight module 1 is used.
What is needed, therefore, is a backlight module in which the FPC and optical films thereof are compactly and stably assembled together, preferably without any gaps therebetween.
In at least one preferred embodiment, a backlight module includes a light guide plate having a light incident surface, a circuit board disposed adjacent to the light incident surface, one or more optical films stacked on the light guide plate, and a fixing means securing the circuit board, the light guide plate and the optical films together.
The fixing means can firmly fix the light guide plate, the circuit board and the optical films together. Thereby, gaps between the optical films and the light guide plate can be avoided.
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, in which:
Reference will now be made to the drawings to describe the preferred embodiments in detail.
The backlight module 2 further includes a circuit board 22, and three light emitting diodes (LED) 21 arranged on the circuit board 22. The circuit board 22 can be a flexible printed circuit (FPC) or a printed circuit board (PCB), and provides power for the LEDs 21. The LEDs 21 are disposed adjacent to the light incident surface 246 of the light guide plate 24. The circuit board 22 is adjacent to the light guide plate 24 at the light incident surface 246, with part of the circuit board 22 overlapping the light emitting surface 248. The circuit board 22 defines two fixing holes 224 corresponding to the protrusions 244.
The side-blocks 646 and the cutouts enable the optical film 662 to be tightly held on the light guide plate 64 without gaps therebetween.
In alternative embodiments, the light guide plates 24, 34, 44, 54, 64 and the circuit boards 22, 32, 42, 52, 62 can be configured with grooves and protrusions respectively, with the grooves of the light guide plates 24-64 engagingly receiving the protrusions of the circuit boards 22-62. In further alternative or supplementary embodiments, the light guide plates 24-64 and the circuit boards 22-62 can be respectively fixed together by a bonding agent such as epoxy applied between the light guide plates 24-64 and the circuit boards 22-62.
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.