本发明揭露一种投影系统，包含一光源、一聚光设备、一成像设备以及一投影镜头。该光源系用以发出一第一光线，该聚光设备则包含一光圈以及一透镜以依序接收该第一光线并产生一第二光线。该成像设备包含一场透镜以及一反射光阀邻近该场透镜，并且该场透镜以及该反射光阀系用以依序接收该第二光线并产生一出射光瞳。该投影镜头具有一入射光瞳大体上重叠该出射光瞳。

The invention discloses a projection system including a light source, a light gathering device, an imaging device, and a projection lens. The light source is used for emitting a first light, and the light gathering device includes an aperture and a lens for receiving the first light in sequence and producing a second light. The imaging device includes a field lens and a reflective valve near the field lens, and the field lens and the reflective valve are used for receiving the second light in sequence and producing an exit pupil. The projection lens has an entrance pupil, and the entrance pupil substantially overlaps the exit pupil.