| 摘要 |
<p>According to a first solution the projector comprises a chamber (1) containing the object whose image is to be projected, a front lens occupying an aperture in one wall of the chamber, made up of two or three single lenses (4), of which at least one of the Fresnel type, having a diameter between 30 and 60 cm, resulting dioptric power between 2 and 5 diopters and presenting between the single lenses a distance between 6 and 8 cm in case of three single lenses and between 8 and 20 cm in case of two single lenses. According to a second solution the projector comprises a chamber to contain the object (22) whose image is to be projected, an aperture in the front wall of the chamber, a concave spherical mirror located in the chamber in a position opposite the above mentioned aperture in such a manner that its center of curvature falls at the side of the aperture, said object being placed near the optical axis passing through said center of curvature and perpendicular to the front wall of the chamber, and being located on the opposite side of the aperture with respect to the optical axis in such a manner that its distance from the concave mirror as measured along the optical axis is greater than r/2 and less than 3.r/4 where r is the radius of curvature of the mirror. <IMAGE></p> |
