Patent ID: 8104898

Claim:
A projection apparatus, comprising: a prism set, comprising: a first prism, having a first surface, a second surface, and a third surface; a second prism, having a fourth surface, a fifth surface, and a sixth surface, wherein the second surface is opposite to the fourth surface, and a gap exists between the second surface and the fourth surface; a light source, providing a non polarized illumination beam, wherein the non polarized illumination beam is incident into the first prism from the first surface, and is reflected by the second surface to be emitted from the third surface; a reflective element, disposed adjacent to the third surface and located on a transmission path of the non polarized illumination beam, after the non polarized illumination beam is reflected by the reflective element, the non polarized illumination beam passes through the third surface, the second surface, the fourth surface, and the fifth surface in sequence; a digital micro-mirror device, disposed adjacent to the fifth surface and located on the transmission path of the non polarized illumination beam reflected by the reflective element, wherein the non polarized illumination beam is converted by the digital micro-mirror device into a non polarized image beam and the non polarized image beam is reflected by the digital micro-mirror device back to the fourth surface, after the non polarized image beam is reflected by the fourth surface, the non polarized image beam passes through the sixth surface; a projection lens, disposed adjacent to the sixth surface and located on a transmission path of the non polarized image beam; and a lens, disposed between the third surface and the reflective element, and located on the transmission path of the non polarized illumination beam emitted from the third surface and on the transmission path of the non polarized illumination beam reflected by the reflective element, to condense the non polarized illumination beam.