| 摘要 |
In producing a motion picture screen from a workpiece by forming a surface with a number of continuously smoothly connected minute projections, a two-dimensional cutter which has a cutting edge constituted by a number of circular arcs connected together in a smooth wavy form lengthwise, each of the arcs having a predetermined curvature rho 1 and a predetermined central angle theta 1, and the centers of the neighboring arcs being on opposite sides of the cutting edge, is used to machine the surface of the workpiece by a relative movement between the workpiece and the cutter. A surface is machined that has in a section perpendicular to the length of the cutter a number of circular arcs connected together in a smooth wavy form lengthwise, each of the arcs having a predetermined curvature of rho 2 and a predetermined central angle theta 2 and the centers of the neighboring arcs being on opposite sides of the line. The workpiece thus machined can have aluminum, etc. applied to it by a vacuum evaporation process, etc. to be directly used as a motion picture screen. Alternatively, the machined workpiece can be used as a mould or die for producing a motion picture screen by pressing a metal foil having a high reflecting property, e.g. an aluminum foil, etc. against the machined surface, the foil forming the motion picture screen.
|
