Patent ID: 8736965

Claim:
A beam combiner for combining a first color light beam, a second color light beam, and a third color light beam to form a composite light beam, comprising: a first lens having a first incidence surface, a second incidence surface, a splitting face, and an exit surface, wherein the first incidence surface is parallel to the splitting face, an included angle between the first incidence surface and the second incidence surface is ninety degrees minus Brewster's angle, the first incidence surface is coated with a first beam-splitting film to allow the first color light beam to transmit through and reflect the second color light beam, and the splitting face is coated with a second beam-splitting film to allow the third color light beam to transmit through and reflect the first light beam and the second color light beam; and a second lens having a third incidence surface and a pass-through face, wherein the third incidence surface is parallel to the exit surface of the first lens and the pass-through face is parallel to the first incidence surface, and the pass-through face faces the splitting face of the first lens; the first color light beam, which is parallel to the second incidence surface, entering the first lens via the first incidence surface with an incidence angle of Brewster's angle, and then emitting to the splitting face to be reflected and come out of the first lens via the exit surface; the second color light beam, which is perpendicular to the second incidence surface and the first color light beam, entering the first lens via the second incidence surface, and then reflected at the first incidence surface and emitting to the splitting face in the same path of the first color beam to be reflected and come out of the first lens via the exit surface in the same path of the first color beam; the third color light beam, which is perpendicular to the third incidence surface and is parallel to the second color light beam, entering the second lens via the third incidence surface, and then leaving the second lens via the pass-through face and entering the first lens via the splitting face to be combined with the first color light beam and the second color light beam to form the composite light beam and come out of the first lens via the exit surface.