1. Field of the Invention
The invention relates to a light guide plate, in particular, to a light guide plate having a two-side composite structure and a manufacturing method thereof combining a screen-printing process and a light-solidification and imprinting process to achieve the advantages of thinning, high transfer ratio, automatic production, and no limitations to production point size.
2. Description of the Prior Art
Among the components of a backlight module, the light guide plate is a key light guide medium applied in the edge type backlight module to guide the direction of light to enhance the brightness of the panel and control the uniformity of the lightness. The appearance of light guide plate can be a wedge type or a flat type. The wedge type light guide plate is usually used in notebook due to the space issue, and the flat type light guide plate is used in LCD monitor and LCD television.
In general, the light guide plate is usually manufactured by an injection molding method, a thermal compression molding method, or a printing method. However, with the increasing of the size of the panel and the requirement of panel thinning, the injection molding method, the thermal compression molding method and the printing method fail to solve many problems respectively as follows.
(1) The problems of the injection molding method includes: (a) the size of the light guide plate is limited, so that the maximum size of the light guide plate practically manufactured is about 32 inch; (b) the thickness of the light guide plate is limited to 2 mm; and (c) the manufacturing cost is higher.
(2) The problems of the thermal compression molding method includes: (a) the transfer ratio of the light guide plate structure is only 70%, and it is too low; and (b) the manufacturing cost is higher.
(3) The problems of the printing method includes: (a) the printing point size will be shifted with the increasing of the number of the manufactured light guide plates, and the point spreading ratio is about 20˜40%; and (b) the printing method fails to provide geometric structures, and only polygon structure and point structure can be manufactured.