Light pipe, color illumination system adopting the light pipe, and projection system employing the color illumination system

A color illumination system comprising:

• a light source producing and radiating light;
• a light pipe, which includes first, second, and third dichroic prisms having first, second, and third mirror planes, respectively, and separates incident light according to a wavelength range and advances separated beams at different angles, wherein the first mirror plane is inclined with respect to the axis of incident light and reflects a first color beam among white light while transmitting other color beams, the second mirror plane is inclined with respect to the axis of incident light and reflects a second color beam among the color beams transmitted by the first dichroic prism while transmitting another color beam, the third mirror plane is inclined with respect to the axis of incident light and reflects a third color beam transmitted by the second dichroic prism, and an exterior of each of the first and second dichroic prisms is formed by additional reflective planes, other than the first and second mirror planes, the additional reflective planes reflect light radiated from the light source that is incident at a predetermined angle due to a difference between the refractive indices of each of the additional reflective planes and the outside so that the incident light travels within the first, second, and third dichroic prisms;
• a first focusing lens focusing the separated beams;
• and
• a scrolling unit which changes the paths of the separated beams focused by the first focusing lens and periodically scrolls the separate beams.

A projection system comprising:

• a light source producing and radiating light;
• a light pipe, which includes first, second, and third dichroic prisms having first, second, and third mirror planes, respectively, and separates incident light according to a wavelength range and advances separated beams at different angles, wherein the first mirror plane is inclined with respect to the axis of incident light and reflects a first color beam among white light while transmitting other color beams, the second mirror plane is inclined with respect to the axis of incident light and reflects a second color beam among the color beams transmitted by the first dichroic prism while transmitting another color beam, the third mirror plane is inclined with respect to the axis of incident light and reflects a third color beam transmitted by the second dichroic prism, and the exterior of each of the first and second dichroic prisms is formed by additional reflective planes, other than the first and second mirror planes, the additional reflective planes reflect light radiated from the light source that is incident at a predetermined angle due to a difference between the refractive indices of each of the additional reflective planes and the outside so that the incident light travels within the first, second, and third dichroic prisms;
• a first focusing lens focusing the separated beams;
• a scrolling unit which changes the paths of the separated beams focused by the first focusing lens and periodically scrolls the separate beams;
• a second focusing lens re-focusing beams transmitted by the scrolling unit;
• a fly-eye lens array delivering the beams transmitted by the scrolling unit;
• a light valve producing an image from beams transmitted by the fly-eye lens array;
• and
• a projection lens unit magnifying the image produced by the light valve and projecting the magnified image onto a screen.