| 摘要 |
An optical system is provided for magnifying the image on a television receiver to viewers in a room. The system is comprised of a plano-convex lens disposed in front of the viewing screen of a television set and a fresnel lens interposed between the viewing screen and the plano-convex lens. The fresnel lens has a smooth surface and an opposite surface configured with a pattern of concentric dioptric ridges facing the plano-convex lens. The magnification achieved by the combination of lenses allows viewers within the room to view a magnified image on the television receiver. Preferably, the planar surface of the plano-convex lens and the smooth surface of said fresnel lens are both disposed to face the television screen so that the television screen can be viewed without significant aberrations or distortion from a wide range of viewing distances.
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