Patent ID: 7066604

Claim:
A light pipe comprising: a first dichroic prism having a first mirror plane, the first mirror plane inclined with respect to the axis of incident light and reflecting a first color beam among white light while transmitting other color beams, the white light being radiated from a light source external to the light pipe; a second dichroic prism having a second mirror plane, the second mirror plane inclined with respect to the axis of incident light and reflecting a second color beam among the color beams transmitted by the first dichroic prism while transmitting the other color beam; and a third dichroic prism having a third mirror plane, the third mirror plane inclined with respect to the axis of incident light and reflecting a third color beam transmitted by the second dichroic prism, wherein each of the first and second dichroic prisms includes 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 color dichroic prisms, and the additional reflective planes form exteriors of the first, second, and third dichroic prisms and contribute to reducing loss in the first, second, and third color beams.