| 摘要 |
<p>HIGH-GAIN PROJECTION SCREEN Lenticular protection screens of improved optical accuracy and uniformity are produced by deriving the specular surfaces of all lenticules within at least a major screen area from a common unitary optical surface, typically using replication by electroforming. The initial master surface is typically formed by conventional machining and polishing of a body having axial symmetry in the general shape of an ogive. The unitary convex surface of revolution of the ogive is repeatedly replicated, and like sections of each replica are isolated and assembled on a transparent reference surface. The assembled sections are adhered to a stiff back, and the optical assembly face is replicated. Multiple replicas of the initial assembly are typically again assembled and replicated, leading ultimately to unitary panel units which form the projection screen. For drive-in theaters or the like, each lenticule is preferably made non-uniform in vertical curvature in a manner which increases the image brightness for a large majority of the viewers. Various shapes of the viewing area can be fitted by suitably formed lenticules. Certain non-symmet-rical viewing areas are closely fitted by tilting symmetrical lenticules about the optical axis of the projector. Reflected light from spurious sources is further reduced by baffles which project toward the audience from boundaries between concave lenticules.</p> |
