Patent ID: 8919968

Claim:
A DMD based projector, comprising: an illumination subsystem, providing a uniform light beam and having: a plurality of light sources; and a light uniform device, comprising: a light incident surface, comprising a first contour; a light emergent surface, being parallel to the light incident surface and comprising a second contour, in which an aspect ratio of the second contour is the same as an aspect ratio of the first contour; and a light uniform body, being defined by four sidewalls which are formed between the light incident surface and the light emergent surface, each of the sidewalls being not uniformly planar, wherein the second contour is projected onto a projection plane to form a first projection area and the first contour is projected onto the projection plane to form a second projection area on the projection plane, in which the first projection area is concentrically rotated with respect to the second projection area along a longitudinal axial direction of the light uniform device at a rotational angle that corresponds to an angle at which the DMD located at the projection plane is rotated relative to the second projection area such that respective corners of the DMD and the first projection area projected on the projection plane substantially coincide, wherein at least one portion of lights of the plural light sources enters the light uniform device from the light incident surface of the light uniform device and emerges through the emergent surface after being uniformed by the light uniform body, wherein the lights emerging from the light emergent surface travel in a direction at a non-inclined angle to the DMD, whereby the lights having the second contour form a bright region that substantially covers the DMD; and an imaging subsystem, comprising: a projection lens.