Patent ID: 6840634

Claim:
A reflective projection display system for receiving a light ray and projecting the light ray onto a screen in a first mode, comprising: a reflective micro-mirror panel having a plurality of micro-mirrors, each of which has a steering shaft and turns around the steering shaft within a specific angle range, to reflect the light ray toward a direction parallel to an optical axis of the reflective projection display system in the first mode and reflect the light ray away from the optical axis of the reflective projection display system in a second mode; a projecting device having a projection lens for receiving the light ray reflected by the reflective micro-mirror panel in the first mode and projecting the light ray onto the screen; and a prism set arranged between the reflective micro-mirror panel and the projecting device, having a first prism, a second prism and a third prism close to the reflective micro-mirror panel, and having a first air gap existing between the first prism and the second prism, a second air gap existing between the third prism and the first prism and between the third prism and the second prism; wherein the light ray is reflected by the first prism before reaching the reflective micro-mirror panel, the light ray reflected by the reflective micro-mirror panel in the first mode directly passes through the prism set and is then received by the projection lens, and the light ray reflected by the reflective micro-mirror panel in the second mode is totally reflected at an interface between the third prism and the second air gap; and wherein a span of the reflective micro-mirror panel in a transversal direction of the screen is smaller than a span of the reflective micro-mirror panel in a longitudinal direction of the screen, and the steering shafts of the micro-mirrors are optically parallel to the longitudinal direction of the screen.