Positioning device for light guide plate and backlight module

#The present invention relates to a technical field of liquid crystal display, and more particularly, to a positioning device for light guide plate and backlight module.

#Backlight module is a vital and key component of the liquid crystal display. Since the liquid crystal panel does not have the capability of illumination, therefore, the backlight module will provide the necessary light beam to the liquid crystal panel. The key function of the backlight module is to provide a light source with sufficient brightness homogeneously distributed such that images and patterns on the liquid crystal display can be readily seen.

#According to the existing technology implemented in the backlight module, the arrangement between the light source and the light guide plate divides into direct-type and side-type. The direct-type is the light source, such as the CCFL or LED are arranged into an array on the backlight module, and then with the help of a diffuser, a prism and optical film to transfer the light source into a surface light to light up the liquid crystal panel. The side-type means the light source is arranged on a side of the light guide plate, and then the light beam is projected into the light guide plate from the side. The light guide plate will then transfer the light source into a surface light to light up the liquid crystal panel. As shown in FIG. 4, the positioning of the light guide plate is shown. In general, the light guide plate 100 is defined with retaining holes 150, and the backboard 200 is formed with corresponding posts 240. With the engagements between the retaining holes 150 and the posts 240 of the backboard 200, the light guide plate 100 can be attached to the backboard 200.

#FIG. 1 is a working principle of a light guide plate of a backlight module made in accordance with the present invention;

#FIG. 2 is an illustrational configuration of a positioning device for a light source of the backlight module made in accordance with the present invention;

#FIG. 3 is a cross sectional view taken along line A-A of FIG. 2;

#In order to make the features and configuration of the present invention readily understandable, a detailed description of preferred embodiments along with accompanied drawings will be given herebelow. Wherein like elements are designed with identical numeral references.

#As shown in FIG. 1, the working principle of the light guide plate 100 can be briefly described as below. In general, the light guide plate 100 is made from optical acrylic or polycarbonate material having high refractive index and low loss. The reflective spots 140 are printed over the acrylic base plate with UV screen-printing technology. The optic-class acrylic board will absorb light, i.e. the light beam comes out of the LED 400 will stay on the surface of the optic-class acrylic board. When the light beam projects from the incident surface 110 to the reflective spot 140, the refracted light beam will be diffused to different directions and angles. Then the refracted light beam will break through the light exiting surface 130 of the light guide plate 100 and project out of the light emitting surface 130. By arranging the reflective spots 140 with different density as well as the sizes, the light guide plate 100 can readily transform the a spot light from the LED 400 into a surface light. On the other hand, a refractive board 600 is provided to refract the diverted light beam back to the light guide plate 100 so as to increase the utilization rate of the light beam. The side-type light guide plate is to arrange the LED 400 on the side of the backboard 200, and then the light guide plate 100 will transfer the light beam into the central area of the screen so as to provide an overall brightness to the interface board. The light guide plate 100 is a key component to the backlight module 10, and the installation or mounting of it will directly affect the quality of the liquid crystal display.

#Referring to FIGS. 6 to 12, the improvement of the present invention is primary focused onto the positioning of the light guide plate. The positioning device includes a backboard 200 and a deformable spring member 300 which can readily deform under external force, and resume to its original shape after the external force is removed. The spring member 300 can be made from metallic material or polymer. The positioning device can be readily implemented into a backlight module of a super-narrow-border liquid crystal display. According to the present invention, the backboard 200 includes a base 210, a pair of longitudinal sidewalls 220 interconnected to the base 210, and a pair of transversal sidewalls 230. The light guide plate 100 is disposed onto the base 210. The light guide plate 100 has a rectangular shape, and includes an incident surface 110, a light-exiting surface 130 adjoining the incident surface 110, and a side surface 120 opposite to the incident surface.