| 摘要 |
An image projection device includes a Fresnel lens positioned in an optical path of an illuminated image in such a way that light from the image passes twice through the Fresnel lens, once in each direction. The first optical element may be a planar mirror arranged to reflect light transmitted by said Fresnel lens in the first direction back through said Fresnel lens in the second direction. In addition, a second optical element may be provided for changing a path of light exiting said Fresnel lens in said second direction so that the projected image appears at a location away from the path of light from the image source to the Fresnel lens. |
