Patent ID: 7909467

Claim:
A beam combiner adapted to a projection apparatus and capable of combining a first color beam, a second color beam, and a third color beam, the beam combiner comprising: a transparent substrate, having a first optical surface and a second optical surface parallel to the first optical surface; a first reflective film, disposed on the first optical surface and capable of reflecting the first color beam; and a second reflective film, disposed on the second optical surface and capable of reflecting the second color beam, wherein the second color beam entering the transparent substrate is reflected by the second reflective film, and leaves the transparent substrate by passing through the first optical surface, and the third color beam enters the transparent substrate from the second optical surface, and leaves the transparent substrate by passing through the first optical surface, and optical paths of the first color beam after reflected by the first optical surface, the second color beam after emerging from the transparent substrate, and the third color beam after emerging from the transparent substrate are substantially coincident.