1. Field of Invention
The present invention relates to color dividing optical device. More particularly, the present invention relates to optical device both of beam splitting and color dividing.
2. Description of Related Art
Digital image is formed from an array of pixels, so as to display an image. Further, for the color image, each pixel is, for example, composed by three sub-pixels of three primary colors in red (R), green (G), and blue (B), so as to express the color shading. Usually, in order to produce the sub-pixels of RGB. Each sub-pixel needs to be implemented with color filter with respect to the desired color. In this manner, the effective portion of the incident light source in white is reduced to ⅓ and the other portion of non-intended colors is absorbed.
For the application in flat displaying apparatus, the back light of the TFT-LCD needs to associate with the gray level modulation of liquid crystal and the color filter, so as to display the color shading of an image. The image sensor in a digital camera, such CCD or CMOS device, also needs the dye-type color filter to display the full-color image of an object. The other applications includes, for example, projector, color video, back-projection TV, . . . , and so on. No matter of single plate, three-plate (TFT-LCD, LCOS) or two-plate prism, all they need to uses the dye-type color filter to express the full color of image. When the system uses the conventional dye-type color filter, each pixel in the color filter can only display single color of the three primary colors R, G, and B. Basically, about ⅔ of the incident white light is absorbed and the light usage rate is reduced. In addition, the battery duration in use for the potable electronic apparatus is also reduced. Further, the fabrication process for the dye-type color filter is rather complicate and the material consumption. The cost for the product and the fabrication factor still remains high.
Some technologies in the art have been proposed for solving the issues, respectively. However, the advantages and disadvantages are both exiting. Therefore, further technologies are still under development.