1. Field of the Invention
The invention relates in general to a diffusion plate of a backlight structure and a display device using the same, and more particularly to a diffusion plate of a backlight structure capable of uniformizing light and a display device using the same.
2. Description of the Related Art
Owing to the progress in the technology of liquid crystal displays (LCDs), and the advantages of LCDs, such as light weight, small volume, lower energy consumption and low radiation, the LCDs are widely applied to all kinds of electronic products, like personal digital assistants (PDAs), notebooks, digital cameras, mobile phones, computer screens and liquid crystal televisions. Furthermore, researches are carried out enthusiastically, and large-scale facilities are used to manufacture the LCDs in the industry, such that the quality of the LCDs is improved, and the cost is lowered. Consequently, the application field of the LCDs expands rapidly. However, the liquid crystal display panel in an LCD is non-self-luminous, and therefore the backlight module is needed for providing light in order to display images. Generally, a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) is the most common light source in the backlight module. Due to the advantages of the light emitting diode, e.g. low electricity consumption and high brightness, the backlight module with the light emitting diode as the light source has become an important research and development subject.
However, the light emitting diode is a point light source, hence a phenomenon called line-mura would easily occur between the light emitting diodes in the backlight module, that is, the brightness of the light provided by the backlight module is not uniform. Generally, to reduce line-mura is to decrease the distance between the light emitting diodes. As a result, the number of the light emitting diodes increases significantly, and the cost of the LCD increases accordingly.
There are several backlight modules for uniformizing light in the prior art. In US Patent Publication Number 20060002148 published on Jan. 5, 2006, an optical member, a backlight assembly having the optical member and a display apparatus having the backlight assembly are disclosed. The optical member includes several luminance uniformity enhancing members. A recessed surface and a light reflecting layer of each luminance uniformity enhancing member are used for uniformizing light. However, the light has been reflected a number of times before passing through a light guide plate, and then finally enters the display panel to display images. In this manner, the brightness of light provided by the backlight assembly is reduced.